"Oh,it is!" said Rabbit."Very uesful too,especially___you need help.横线上填什么单词?

问题描述:

"Oh,it is!" said Rabbit."Very uesful too,especially___you need help.横线上填什么单词?

when 状语从句
Rabbit说它也是非常有用的,尤其是当你需要帮助的时候