Question

No one can walk the wire in the air without a bit of fear unless ______ very young.

A．having trained	B．trained
C．to be trained	D．being trained

Answer 1

B

解析这题考查条件状语从句的省略，英语中，如果主从句的主语一致，可以省略从句中的主语和be动词，像这题，完整的表达应该是：unless he is trained young，省略he is后就剩下trained，选B。