1 ____ time ,he will make a first-class tennis player .
A Having given B To give C Giving D Given
2 ___in 1636 ,Harvard is one of the most famous universities in the United States .
A Being founded B It was founded
3 Unless __to speak ,you should remain silent at the conference .
C being invited D having invited
4 ___,but he still couldn’t understand it .
A He had been told many times
B Having been told many times
D Although he had been told many times
5 When first ___to the market , these products enjoyed great success .
A introducing B introduced
C introduce D being introduced
6 There seemed to be nothing ___to do but ___for the doctor .
A leave / send B left / to send
C left / send D leaving / send
作介词but ,expect ,besides 的宾语，前面又有实意动词 do时，不定式通常省去to
