The theory ________ by Einstein was later to prove true, but at that time few people could accept it.
| A．put out | B．put together | C．put aside | D．put forward |
. There are so many kinds of tape-recorders on sale that I can’t make up my mind ____to buy.
| A．what | B．which | C．how | D．Where |
. Charles Babbage is generally considered _______ the first computer.
| A．to invent | B．inventing | C．to have invented | D．having invented |
. The missing boys were last seen _______ near the river.
| A．playing | B．to be playing | C．play | D．to play |
. The patient was warned _______ oily food after the operation.
| A．to eat not | B．eating not | C．not to eat | D．not eating |
. I regret _______ you that we are unable to offer you employment.
| A．informing | B．having informed | C．to inform | D．to informing |