We were told that ______ when Marx was already _______, he started to learn Russian.
| A．in 1840’s; in his fifties | B．in the 1840’s; his fifties |
| C．in the 1840’s; in his fifties | D．the 1840’s; in his fifties |
The problemsat the meeting tomorrow are really hard to solve.
| A．discussed | B．to discuss | C．to be discussed | D．discussing |
___ surprised me most was ____ he was too late for the important meeting, for he was chairman of it.
| A．What; why | B．That; how | C．What; how | D．That; why |
_______ all the inventions have in common is _____they have succeeded.
A. What; what B. That; that C. What; that D That; what
Only when I read this story for a second time to appreciate its beauty.
| A．had I began | B．that I began | C．I began | D．did I begin |
By the time you have completed the essential training, you _____ exposed to virtually every new feature of the course．
| A．are | B．will have been | C．have been | D．will be |