By the time Einstein was 14 years old, he ________ himself advanced mathematics.
| A．has taught | B．taught |
| C．had taught | D．was teaching |
----- Is that Mr．Smith over there?
----- No, it _____ be him --- I am sure he is much taller.
| A．must not | B．may not |
| C．can’t | D．won’t |
---Is it good to look up every new word when I come across it in reading?
---No. You ______because you are likely to guess the meaning from the context.
A. can’t B. mustn’t C. don’t have to C. ought not to
—Shall we go out for______ meal this evening?
—Yes，that’s_____ good idea．
| A．a：a | B．a；the | C．the；a | D．the；the |
I don't know if you noticed their behaviors or not, but we______.
| A．were | B． have | C． had | D． did |
Here is the tower, ______ top you can have a good view of the whole city.
| A．from whose | B．from its | C．over whose | D．whose |