11. ___________life exists on any other planet in the solar system still remains a question.

10. What an ___________ (exhaust) day ！ After a whole day's hiking, I am completely___________ (exhaust).

9. The rivers are polluted so seriously that fish are ___________(float)on the surface, dead.

8. If you feel unwilling to talk about something you'd rather not, say ___________ (gentle) but firmly, "I'd like
to change the subject."

7. Newborn babies are good sleepers. The amount of their sleep is several times ___________ (large) than that of
adults.

6. ―Thank God you're safe ！

―I stepped back, just in time ___________ (avoid)the racing car.

.

5. Air pollution will get worse and this will be ___________(harm) to people; for example, it can cause cancer.

4. Seeing the bad results of the exams, the student was rather sad and felt ___________ (puzzle) about her future

3. They produced young generally by ___________(lay)eggs.

2. What prevented him ___________(attend) the meeting yesterday is that his mother was ill then.