.After the clock twelve, the students walked out of the lecture room.
| A．beat | B．bit | C．struck | D．rang |
When I went in , they were ____ in a heated discussion .
| A．absorb | B．absorbed | C．absorbing | D．being absorbed |
The ________ for tonight’s talk is protecting the environmet.
| A．title | B．subject | C．news | D．theme |
You can't camp________you like these days. Many natural areas are now under protection.
| A．whichever | B．wherever | C．what | D．when |
The samples__________in quality but were general acceptable．
| A．varied | B．changed | C．disagreed | D．Exchanged |
Cleaning women in big cities get _____ by the hour.
| A．pay | B．paying | C．paid | D．to pay |