机床分度蜗轮偏心会导致齿轮的径向误差。（)

A．文章的难度数值

B．文章所含的单词数量

C．理解文章所需的词汇量

D．文章适合的美国学生年级

A．standard

B．level

C．pollution

D．grade

Which exertion level should you intend to reach？

Between grade ______.

A．if(score>=90) grade='A'; if(score>=60) grade='P'; if(score<60) grade="E" ;>

B．if(score>=90) grade='A'; if(score<90 && score>=60) grade='P'; if(score<60) grade="E" ;>

C．if(score>=90) grade=A; else if(score>=60) grade=P; else grade=E;

D．if(score>=90) grade='A'; else (score<90 && score>=60) grade='P'; else (score<60) grade="E" ;>

A．sample

B．population

C．variable

D．statistic

E．parameter

A、Focus on process.

B、Combine listening with other skills.

C、Focus on the comprehension of meaning.

D、Grade difficulty level appropriately.

A．have a hard struggle or fight

B．raise to a higher grade

C．come to a lower level or state

D．make the greatest possible use of