Weknowthatasmileisusuallyasignthatpeoplefeelfriendlyand...

问题详情：

We know that a smile is usually a sign that people feel friendly and happy，but _____ we don't know who the new person is？（　　）

A．what if   B．how come    C．what about  D．why not

【回答】

A

知识点：固定句型

题型：选择题