When first to the market, these products enjoy great success.
| A．introducing | B．introduced |
| C．introduce | D．being introduced |
It was not until 1920regular radio broadcast began.
| A．while | B．which | C．that | D．since |
Generally speaking,according to the directions,the drug has no side effect.
| A．when taking | B．when taken |
| C．when to take | D．when to be taken |
Theyus on duck and green peas.
| A．serve | B．feed | C．feast | D．treat |
—Shall we go swimming?
—OK.I’ll go and get.
| A．changed | B．to change |
| C．to be changed | D．changing |
The two brothers look so much alike that it is difficult to.
| A．tell them from | B．tell from them |
| C．tell them apart | D．tell apart them |