例句與造句

1. The expected 2＋2 cycloadduct (79) was not observed .
   未見到所預(yù)期的22環(huán)加成物（79）
2. The expected 2 2 cycloadduct ( 79 ) was not observed
   未見到所預(yù)期的2 2環(huán)加成物（ 79 ）
3. It's difficult to find cycloadduct in a sentence. 用cycloadduct造句挺難的