On reaching home I discovered that I ____ my keys at the office.
A. left B. have left C. was left D. had left
By the time she leaves the stage next month, she ____ for sixty years.
A. will have performed B. has performed
C. will be performing D. will perform
从选项看考查时态，选项A或B是正确答案，从时间状语看By the time she leaves A正确。
I appreciate ____ to your school to give a lecture.
A. to be invited B. to have invited
C. having invited D. being invited
The plants would have grown all right if she ____ them properly.
A. had watered B. watered C. has watered D. waters
All the evidence pointed to the conclusion ____ he was guilty.
A. which B. that C. as D. so
____ she likes the present is not clear to me.
A. If B. What C. Which D. Whether
John made her ____ him everything about her plan for the trip.
A. to tell B. tell C. told D. tells
I can't help ____ whether we should go without raincoats.
A. wonder B. to wonder C. wondering D. wondered
Never in her life ____ in such an important party, where she saw so many pop stars.
A. Lisa took part B. did Lisa take part
C. Lisa was taken part D. was Lisa taken part
The young man, ____ met us at the station yesterday, will show us around the campus this morning.
A. who B. that C. which D. whose
从选项看考查从句，位于名词的后面考查定语从句或者同位语从句，看试题考查定语从句代替前面的名词the young man，因为选择A。