—How long _______it _______ you to work out such a difficult problem?
—About thirty minutes.
A. did… take B. does… take C. did…cost
–The weather is very cold these days. –.
A. So do I B. So is itC. So it is
There is no _____ that phones play an important role in the modern life.
A.question B. doubt C. problem
There ______ more new buildings in my hometown in two years .
A. are B. will haveC. will be
The little boy is healthy, _____ he is happy, too.
A.and B. but C.or
The meeting for two hours.
A. has begun B. has been onC. began