1. ____ number of books have been given to the library. As a result, ____ number of books is becoming larger and larger.
A. A, a B. A, the C. The, a D. The, the
2. He joined the army two years ago. In other words, he has _____ the army for two years.
A. been in B. joined C. joined in D. in
3. _____ is important ____ us to learn English well.
A. It, for B. That, for C. It, of D. This, of
