几道英语时态题

几道英语时态题
1.If it ___ too much trouble,i'd love a cup of tea.
A isn'tBwasn'tC weren't D hadn't been
2.You can go a take a rest.i'll see to it that the job ___finished in time.
A must beB isC beD has
3.The car ___ at eleven to collect the guest speakers and they__ at the hall eleven thirty.
A will come;arriveB comes;have arrived
C comes;arriveD has come;arrive
4"when are you leaving?"
"My plane ___at 10:45"
A took offB is about to take offC will take off D takes off
5 If you climb mountains in such bad weather,you___trouble.
A ask for B have asked forC will ask forD are asking for
答案是ABCDD 请解释下为什么.