1.The research is so designed that once__nothing can be done

1.The research is so designed that once__nothing can be done to change it.
A.begins B.having begun C.beginning D.begun
2.Can___be in the desk___you have put my letter?
A.it;which B.I;which C.you;in which D.it;that
3.Never___time come back again.
A.has lost B.will lose C.will lost D.lose
4.I have nothing to confess____you want me to say?
A.What is it that B.What it is what C.How is it that D.How it is that
5.Is this factory____you visited the other day?
A.the one B.that C.where D.when
6.Was it____she heard with her ears___really made her frightened?
A.What;that B.it;that C.that;which D.what;/
7.____What the six blind men said sounded?
A.How foolishly B.How foolish C.What foolishly D.What foolish
8.It was___the old clock that the old man spent the whole morning at home.
A.repair B.repairing C.to repair D.in repair
9.-Was it under the tree___you were away talking to a friend?
-Sure.But when i got back there,the bike was gone.
A.that B.where C.which D.while
10.Not far from the club there was a garden,___owner seat in it playing bridge with his children every afternoon.
A.whose B.its C.which D.that
11.Thank you for the trouble you have___to help me.
A.paid B.taken C.had D.asked
12.He insisted that the sky____clear up the following day.
A.would B.should C./ D.be
13.-Please make my excuse at tomorrow's meeting.
-I've got too much work_____.
A.to do to come B.doning come C.to do coming D.doing to come
14.Who is it up____decide whether to go or not?
A.to to B.for for C.to for D.for to