题目内容：

Welcome to our idiom (习语) corner!

1.Picture _____ can be chosen to express “to do something without thinking”.

2.We can’t believe Robert won this watch. He’s really _______.

A. a walking man    B. a trigger    C. a dark horse    D. an egg

3.The Chinese meaning to the idiom “to walk on air” is probably “________”.

A. 一无所有    B. 欢天喜地    C. 愁眉苦脸    D. 不假思索

4.The writer didn’t use _______ to help the readers understand the idioms above.

A. explanations (解释)    B. pictures    C. examples    D. results