--- This math problem is _____ hard for me to understand. Can you help me ?----Sure. It’s my pleasure.
Air pollution does harm to people’s health.A. very B. little C. great
.I'm sorry you've missed the train .It _______ for 10 minutes .A. has left B. has been away from C.has been away
---- What are you going to do this weekend ? ---- I'm going to do some outdoor activities _______ it rains .A. If B. unless C. because
She has succeeded in _____ the problem. A. solving B.solve C.to solve
---- Would you like a hamburger or a hot dog ? ----_______ is OK . I really don't mind .A. Either B. None C. Neither