Question

Only when he put his foot into the river________that the water was too cold to swim in.

1. A.
   he realized
2. B.
   did he realize
3. C.
   had he realized
4. D.
   he had realized

Answer 1

B

试题分析：考查倒装，only＋状语(状语从句)放句首时，主句要用倒装语序所以选B
考点：考查倒装
点评：不完全倒装，是把助动词提前；而完全倒装是把动词放在主语的前面。注意句子when he put his foot into the rive…是 when引导的时间状语从句。句子that the water was too cold to swim in.是个宾语从句。