（ ）1.Bob insisted that the invitation ____ to them at once.
A.would be sent B.should send
C.must be send D.be sent
（ ）2.The guests will be here ____ two o'clock.
A.in B.on C.for D.by
( )3.Who must be sent ____ the accident?
A.for;for B.to;for
C.for D.to
( )4.Look ____ the left and see if the dog is there.
A.to B.at C.on D.for
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