无论酸还是碱催化下的酮的α-H的卤代反应,烯醇化一步都是决带步骤。( )
查看答案
when is Mid-Autumn Festival ?
A. the 15th day of the 8th lumar month
B. August 15th in the calendar
C. full moon day
Paul and Sue decided to go to a restaurant. They reserved a table. But the restaurant was almost empty. So they ________________ a table.
A. mustn't reserve
B. needn't reserve
C. couldn't have reserved
D. needn't have reserved
A: I got very wet walking home in the rain last night. B: Why did you walk? You ___________ a taxi.
A. could take
B. can take
C. could have taken
D. must have taken
I left my bike outside the house last night and now it’s gone. Somebody __________
A. must have taken it
B. should have taken it
C. must take it
D. would have taken it