The first thing___you should do is to learn all the new word by heart.A.what B.that C.which
问题描述：
The first thing___you should do is to learn all the new word by heart.A.what B.that C.which
答
选B,老师说过,先行词中有序数次要用that
答
that
定语从句中，先行词有序数词或者*修饰（本题为first），只能用that。
答
你好.
选B.因为词中有序数词,所以要用that进行修饰 .