在下图所示的轮系中，已知双头右旋蜗杆的转速n1=900r／min，转向如图所示，z2=60，z2'=25，z3=20，z3'=25，

The major difference between modern private and public libraries lies in

A．readership.

B．content.

C．service.

D．function.

A、The difference in languages spoken by people from difference countries.

B、The difference in age between the people communicating.

C、The difference in jobs between the people communicating.

D、The difference between high and low-context communication.

What is the difference between the major and minor premises？

A、The major premise is usually a more important and lengthy claim while the minor one is less important and lengthy.

B、The major premise is usually a broad and generally recognized truth, while the minor one is a more specific and narrowly applicable fact.

C、Major claim connotes minor claim.

D、The major premise major is usually a more specific and narrowly applicable fact while the minor one is a broad and generally applicable truth.

The major difference between Dr. Vink and other geneticists is that

A．her research is not based on the study of twins but on questionnaires.

B．her research does not emphasize the contrast between two kinds of twins.

C．her research is interested in the smoking habits of fraternal twins.

D．her research only focuses on the study of the DNA of adult twins.