Question

2. Body language is an international language, and        ， you Ml make a fool of yourself on many an occasion. (lack)

身体语言是一门国际通用语。缺乏常识，你就会在许多场合出洋相。

Answer 1

2. lacking (for) / if you lack (for) the common knowledge 考查分词结构或条件状语从句及lack的用法。lack (for) sth.缺乏某事。and连接的是并列句。因第二个分句缺少条件句，故用if_you lack (for) the common knowledge。由于从句中的主语与主句的主语一致，可以将从句改成现在分词短语。