The scientists were waiting to see the problem ____ 　.　
　 A. settle　　　         B. settled　　　         C. to settle　　　         D. settling

 The foreigner tried his best, but he still couldn't make his point ____ 　.
　 A. understand　    B. understanding 　        C. to understand 　         D. understood

 People ____ in the city do not know the pleasure of country life.
　 A. live　　　         B. to live　　　         C. lived　　　         D. living

 The ____ price will save you one dollar for each dozen.
　 A. reduce　　　         B. reducing　　　         C. reduced　　　         D. reduces

 The student corrected his paper carefully, 　____ the professor's suggestions.　
　 A. follow　　         B. following  　        C. followed　         D. being followed

 He went from door to door, ____ waste papers and magazines.　
　 A. gathering　　　        B. gathered  　        C. gather　　　         D. being gathered

 ____ the office, the foreign visitors were shown round the teaching building. 　
　 A. Having shown　 B. Showing   　 C. Has shown　　         D. Having been shown

 With winter ____ on, it's time to buy warm clothes.　　
　 A. came　　　         B. comes　　　         C. come　　　         D. coming

 Deeply _____ , I thanked her again and again.　　
　 A. being moving　        B. moved　     C. moving　　　         D. to be moved

 ____ how to do the homework, I went to ask my teacher for help.
　 A. Not to know　　     B. Not knowing     C. Knowing not　　         D. Not known