18．When knowing that the experiment will end in _____ failure, Jack thinks that he is _____failure.
A. a; / B. /; a C a; a D. /; /
19．If this bill is not paid within five days, your gas supply will be _______.
A. cut down B. cut up C. cut out D. cut off
20．---Mary has been trained hard for the last two years.
---______she did so well at the track and field meet yesterday.
A. No doubt B. No question C. No wonder D. No problem
