设某产品生产x单位的总收益R为x的函数 R=R（x)=200x-0.01x2 求：生产50单位产品时的总收益及平均单位产品的

听力原文：W: Professor, have you graded my term paper yet？

M: To tell you the truth, I've been tied up in committee meetings all week.

Q: What can be inferred about the conversation？

(13)

A．The professor has graded the paper.

B．The professor has been in the meeting all week.

C．The professor hates to grade the paper.

D．The professor has read his paper on the meeting.

A．The professor has graded the paper.

B．The professor has been in the meeting all week.

C．The professor hate, to grade the paper.

D．The professor has read his paper on the meeting.

My English teacher ______ my test.

A、has not yet graded

B、has not yet been graded

C、is not yet to be graded

D、is not yet graded

Products are graded according to size and().

A、quality

B、quantity

C、qualification

The second paragraph proposes that supplementary graded reading materials should ______.

A．be interesting enough to attract readers

B．be simplified so as to fit the learners' level of proficiency

C．take into consideration the learners' proficiency in English and reading interests

D．not be simplified and graded

initial crack tip lies in the graded material or in the more ductile material (and thereafter advances across the graded layer.

A、tends

B、whether

C、thereafter

D、lies in

The second paragraph proposes that supplementary graded reading materials should ______.

A．be interesting enough to attract learners

B．be simplified so as to fit the learners' level of proficiency

C．take into consideration not only the learners' proficiency in English but also their reading interests

D．not be simplified and graded

The view (which) elements of a culture are to be understood and judged (in terms of) their relationship to (the culture as a whole) led to the conclusion that the cultures themselves could not be (evaluated or graded as) higher and lower, superior or

A．which

B．in terms of

C．the culture as a whole

D．evaluated or graded as

A.She has just graduated．

B.She hasn’t graded the papers yet．

C.She isn’t his sister．

D.She’s still a student．