I think the first lesson we are learning is very easy.
- A.that
- B.where
- C.who
- D.when
答案
正确答案:A
知识点:定语从句

根据语境,先行词the first lesson在从句“we are learning…”中做宾语,且先行词为物,故关系词可选用which或that。但由于有序数词first修饰,所以只能用that。正确答案为A。

略
