Question

Though ________, swimming does us much good．

1. A.
   tired
2. B.
   we tire out
3. C.
   tiring
4. D.
   it is tired

Answer 1

C
解析：
分析句子的结构和逻辑关系，此句前后是让步关系。可以把though remember 看成是一个省略句，相当于：Though swimming is tiring，这里swimming与tiring是系表结构，表示属性，所以选tiring。