1. The whole book ______ twelve units, _____ two that are mainly for revision.
A. contains, including B. includes, containing C. contains, containing D. includes, including
2. I told my brother not everyone could work out the problems as quickly as him, _________?
A. could he B. didn’t I C. didn’t he D. could they
3. It is uncertain what _____ the new medicine will have on children, though it has been tested on adults.
A. effects B. systems C. failures D. abilities
