Failure is never pleasurable, but it can make a positive contribution to your life ____ you learn to use it.
| A．since | B．once | C．until | D．unless |
Climbing hills__________of great help to health.
| A．is | B．are | C．were | D．be |
Her family__________much larger than mine four years ago.Her family__________dancing and singing when I came in last night.
| A．were; was |
| B．was; were |
| C．was; was |
| D．were; were |
A knife and a fork __________on the table.A knife and fork __________on the table.
| A．is; is | B．are; are | C．are; is | D．is; are |
Many a professor__________looking forward to visiting Germany now.Many scientists
__________studied animals and plants in the last two years.
| A．is; have | B．is; has | C．are; have | D．is; are |
He is one of the boys who__________here on time.He is the only one of the boys who
__________here on time.
| A．has come; have come |
| B．have come; has come |
| C．has come; has come |
| D．have come; have come |