13. --Hi, Lydia. Are you going to the concert on Friday? - -I’d like to. But there are so many problems ____.
It is by no means clear the president can do to end the strike.
(年北京市西城区高三5月二模试题)31. A person who has never tasted bitter won’t know ______ sweet is.
It suddenly occurred to him he had left his keys in the office.
(年北京市西城区高三5月二模试题)23. It’s been discovered in the study ______ people are more relieved after forgiving others.
The last time we had great fun was _____ we were visiting the Water Park.