主谓一致专项练( ) 1. One-third of the area _ covered with green trees. About seventy percent of the trees _ been planted. A. are; have B. is; has C. is; have D. are; has ( ) 2. The number of teachers in our college _ greatly increased last term. A number of teachers in this school _ from the countryside. A. was; is B. was; are C. were; are D. were; is ( ) 3. What _ the population of China? One-third of the population _
