问题

When ______ comes to research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals

A:that
B:it
C:this
D:what

正确答案是：

同类题型

MrWhite tohospital for an examination yesterday but he was too busy to come

We got here on Tuesday afternoon. -_______ Why didn’t you call us earlier’

His daughter was disabled after a serious illness in 2003 and in the last seven years, hemoney to help those children like his daughter

These flowers are made paper and they look very beautiful.

How I wish I________ to repair the TV! I only made it worse .