Heconcludedhisspeechwitharemarkthatfailure____themotherofsuccess.
A、musthavelastedB
【句意】本期设计联络会将持续十天才会结束。
【难点】by the time意指no later than the moment that something happens，常与过去完成时和将来完成时连用。
Mycoat__________therebehindthedoor.Can’tyouseeit?
I’d rather you ____ by train because the weather forecast said there would be heavy snow tomorrow.
It’s necessary ______ us to keep our pets clean everyday.
Howlonghaveyou____?
Hearrived____London____acoldwinternight.
