16. I promise I'll remember ______ the book to you.
A. return
B. to return
C. returning
D. returned
17. They _______ several extra bus lines during the rush hours.
A. get
B. have
C. run
D. take
18. Julia _____ a pleasant hour talking with friends.
A. spent
B. took
C. went
D. cost
19. They succeeded _____ overcoming the difficulties they encountered.
A. to
B. on
C. in
D. of
20. I'll not go to the party _______ I am invited.
A. or
B. till
C. unless
D. when
III. 语法选择填空（每小题的A. B. C. DL四个答案中，选出一个正确答案，对原文不得作任何改动。 每小题1分，共20分）
1. The project _______- by the end of 1998.
A. had been completed
B. had completed
C. has been completed
D. has completed
2. You are the only person here ________ knows me.
A. whom
B. one
C. which
D. who
