It took many hours to convince John ________ his wife's mistake．

of

at

on

for

It was the training ________ he had as a young man ________ made him such a good engineer．

what; what

which; that

that; which

that; what

More natural resources should be made use of ________ the ________ need of energy．

meeting; increasing

to meet; increased

meeting; increased

to meet; increasing

We ________ my uncle who was working in Sichuan when the earthquake happened．

were concerned about

are concerned in

are concerning over

concerned

You are doing it in a wrong way．It ________ in this way．

used to do

is used to doing

used to be done

is used to do

The air force of that country is ________ the command of General Hall．

at

with

under

in

The water of the lake is so ________ that it looks like glass．

calm

rapid

silent

quiet

She ________ into the forest alone on such a dark night．

dares not go

dares not to go

dare not to go

doesn't dare to go

John ________ his promise．I wonder why he changed his idea．

need keep

should have kept

must have kept

will keep

The injured man was still ________．

suffer

suffered

to suffer

suffering