Question

When he left,his motherz(） A is cooking Bcooked Cwas cooking D cooks

We'll go to play with snow if it (）tomorrow Asnow Bsnows Cwill snow D snowed
There()some milk in the glassAhave B has Care D is
The train(）when we got to the station A has just left B had just left Cleaves D left

Answer 1

CCAB

Answer 2

cbbb

Answer 3

C B D B

Answer 4

1.When he left,his mother (c） A is cooking Bcooked Cwas cooking D cooks 过去进行时2.We'll go to play with snow if it (B）tomorrow Asnow Bsnows Cwill snow D snowed
if引导的条件状语从句，主句将来时，从句要用一般现在时，所以用B3.There(D)some milk in the glassAhave B has Care D is (milk是不可数名词，用单数）
4. The train(B）when we got to the station A has just left B had just left Cleaves D left （当我们到底车站的时候，火车已经开走了，表达的是“过去的过去”，所以用过去完成时）