Limited Duty Officer: due to the highly technical nature of some officer billets, the Marine Corps, Navy and Coast Guard employ a system of promoting proven senior enlisted members to the ranks of commissioned officers. They fill a need that is similar to, but distinct from that filled by warrant officers (to the point where their accession is through the same school). While warrant officers remain technical experts, LDOs take on the role of a generalist, like that of officers commissioned through more traditional sources. LDOs are limited, not by their authority, but by the types of billets they are allowed to fill. However, in recent times they have come to be used more and more like their more-traditional counterparts.

If you are pressed for time, it may be worthwhile to look into future ASVAB test dates in order to plan ahead in case you get a poor score on your upcoming ASVAB test. You can check with your high school counselor or your military recruiter to make sure that you will be eligible to take future tests along with your planned upcoming test date in the event that you get a bad ASVAB score.
Because most of the concepts and methods used by the military, and many of its systems are not found in commercial branches, much of the material is researched, designed, developed, and offered for inclusion in arsenals by military science organisations within the overall structure of the military. Military scientists are therefore found to interact with all Arms and Services of the armed forces, and at all levels of the military hierarchy of command.
The AFQT score is a percentile score. What does that mean? In 1997, a study, known as the "Profile of American Youth," was conducted by the Department of Defense in cooperation with the Department of Labor. DOD administered the ASVAB to around 12,000 individuals, ranging in age from 16 to 23. Your AFQT score is a comparison of how well you scored on the four subtests, compared to those who took the ASVAB as part of the 1997 survey. In other words, if you have an AFQT score of 70, that means you scored as well or better than 70 percent of those 12,000 folks.
As of 31 December 2010, U.S. Armed Forces troops were stationed in 150 countries; the number of non-contingent deployments per country ranges from 1 in Suriname to over 50,000 in Germany.[30] Some of the largest deployments are: 103,700 in Afghanistan, 52,440 in Germany (see list), 35,688 in Japan (USFJ), 28,500 in South Korea (USFK), 9,660 in Italy and 9,015 in the United Kingdom. These numbers change frequently due to the regular recall and deployment of units.
The other written test format is the Student ASVAB which is given at high schools, vocational schools, or colleges. This test lasts approximately three hours. The Written Arithmetic Reasoning subtest of the ASVAB consists of 30 multiple choice questions, which must be answered in 36 minutes. Below are a few sample questions which are very similar to the actual questions you'll see on the ASVAB:

Although mostly concerned with the military transport, as a means of delivery using different modes of transport; from military trucks, to container ships operating from permanent military base, it also involves creating field supply dumps at the rear of the combat zone, and even forward supply points in specific unit's Tactical Area of Responsibility.
The ASVAB is a series of tests developed by the Department of Defense and is used by the U.S. Army to determine whether you have the mental aptitude to enlist. The ASVAB also helps determine which Military Occupational Specialties (MOS) you qualify for. The ASVAB is required to enlist in the U.S. Army and is valid for two years. The ASVAB may be given in a computerized version at a Military Entrance Processing Station (MEPS) or in a paper version at various Military Entrance Test (MET) sites around the country or at high schools and colleges. 
The way to prepare for this exam is study hard and then quiz yourself with plenty of practice ASVAB tests. Remember that the exam is identical for all branches, so an Army ASVAB practice test is exactly the same as an ASVAB practice test for the Navy. The most important components of the test are the ones that count towards the Armed Services Qualifications Test, or AFQT. These sections are Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, and Math Knowledge. For tips and strategies for success on these questions, be sure to review our article on ASVAB Test Prep.
AFQT scores are grouped into five main categories based on the percentile score ranges. Categories III and IV are divided into subgroups because the services sometimes use this chart for internal tracking purposes, enlistment limits, and enlistment incentives. Based on your scores, the military decides how trainable you may be to perform jobs in the service.
The ASVAB was created in 1968. By 1976, all branches of the military began using this test. In 2002, the test underwent many revisions, but its main goal of gauging a person’s basic skills remained the same. Today, there is a computerized version of the test as well as a written version. The Department of Defense developed this test and it’s taken by students in thousands of schools across the country. It is also given at Military Entrance Processing Stations (MEPS).
Under the Student Loan Repayment Program, when you enlist the Army will pay back up to $65,000 in qualified education loans (up to $20,000 for reservists), the Navy up to $65,000 and the Air Force up to $10,000. Each year 15% of the loan balance or $500, whichever is greater, will be repaid by SLRP. There may also be annual and cumulative caps on the amount repaid. Participants must score 50 or higher on the Armed Forces Qualifications Test (AFQT). SLRP must be requested at the time of enlistment or reenlistment. Qualified education loans include federal education loans such as the Perkins, Stafford, PLUS, or Consolidation loans, but not private alternative loans. Defaulted loans are not eligible. Payments made under the SLRP are considered taxable income.
These tests, again the high quality ones, are formatted like the real thing so you can get used to the question and answer formats and the time limits so nothing will be a surprise on test day. You’ll know what to expect and you’ll be used to going from different concept to different concept as is often required on the ASVAB. For example, on the math section you may have a problem using one popular math principle followed by another problem that relies on a completely different principle. This is common on a broad test like the ASVAB and preparing your mind to make these leaps can allow you to answer more questions in less time and boost your score.
These scores include your Armed Forces Qualification Test (AFQT) score as well as your scores on each of the 9 individual subtests that make up the ASVAB.  When you get your report, the most important score you will want to look for first is your AFQT score.  This score determines your eligibility to serve in the military and to enlist in the U.S. Marines you need to have achieved a score of at least 32.
Note: While the U.S. Navy is older than the Marine Corps,[52] the Marine Corps takes precedence due to previous inconsistencies in the Navy's birth date. The Marine Corps has recognized its observed birth date on a more consistent basis. The Second Continental Congress is considered to have established the Navy on 13 October 1775 by authorizing the purchase of ships, but did not actually pass the "Rules for the Regulation of the Navy of the United Colonies" until 27 November 1775.[53] The Marine Corps was established by act of said Congress on 10 November 1775. The Navy did not officially recognize 13 October 1775 as its birth date until 1972, when then–Chief of Naval Operations Admiral Elmo Zumwalt authorized it to be observed as such.[52]
There is another ASVAB score that's equally important, if not more so, because it is the score that determines if a person is eligible for military service. It's the Armed Forces Qualification Test score, or AFQT score. This score is calculated from only four of the nine Standard Scores on the ASVAB - Arithmetic Reasoning (AR), Mathematics Knowledge (MK), Paragraph Comprehension (PC), and Word Knowledge (WK). First, the WK and PC scores are added together, then the sum is doubled. This is known as the Verbal Expression (VE) score. The VE, MK, and AR scores are then added together, and the sum is the AFQT. This score is a straight percentile measure, expressed as a number from 1-99. The number is the percentage of people who scored lower than the test taker. For example, if a person receives an AFQT score of 63, that means that he did better on the test than 63% of the people who have taken it.

SOC is a consortium of more than 1550 colleges and universities that provide educational opportunities for servicemembers and their families. It is co-sponsored by the American Association of State Colleges and Universities (AASCU) and the American Association of Community Colleges (AACC) and managed for the DoD by the Defense Activity for Non-Traditional Education Support (DANTES). Course work can be done on campus, at military installations and armories, and at a distance by computer or correspondence. Associate, bachelor, and graduate-level degree programs are available. Special curriculum areas include SOCAD (Army), SOCNAV (Navy), SOCMAR (Marines), and SOCGuard (Army National Guard). In addition, SOC operates ConAP (Concurrent Admissions Program) to increase college enrollment of Army enlistees (Army and Army Reserves). ConAP allows you to enlist in the Army at the same time as you apply for college. DANTES also operates its own Distance Learning Program. For more information, contact: