_______ you may have, you should gather your courage to face the challenge.
A. However a serious problem
B. What a serious problem
C. However serious a problem
D. What serious a problem
It is uncertain ________ side effect the medicine will bring about, although about two thousand patients have taken it.
A. that B. what C. now D. whether
A lot of language learning,________ has been discovered, is happening in the first year of life, so parents should talk much to their children during that period.
A. as B. it C. which D. this
Between the two parts of the concert is an interval,________ the audience can buy ice-cream.
A. when B. where C. that D. which
The printer is of good quality. If it ________ break down within the first year, we would repair it at our expense.
A. would B. should C. could D. might
They use computers to keep the traffic _________ smoothly.
A. being run B. run
C. to run D. running
