20. _________raining hard for 3 hours without stopping.
21.
| A．It is | B．It was | C．It has been | D．It had been |
The little boy got rice to feed the chickens in the yard.
| A．a piece of | B．a number of | C．a handful of | D．a loaf of |
Not until all the fish died in the river how serious the problem of water pollution was.
| A．did they realize | B．they did realize | C．had they realized | D．they had realized |
When I was twenty, I had to before graduation and work in a clothes shop to help support my family.
| A．come out | B．stay out | C．leave out | D．drop out |
After the quarrel, I tried all my best to fix the misunderstanding between us, but all my efforts seemed .
| A．in vain | B．in case | C．in time | D．in trouble |
Though many extra planes and trains are used to carry passengers, traffic tools are still
needed during “May Day” holidays.[
| A．eagerly | B．badly | C．equally | D．slightly |