Question

What___you do when you were five years old?你5岁的时候会做些什么?

Answer 1

What 【could】you do when you were five years old? 你五岁时会做什么？
这里的“会”表示能力，所以用could而不是would；后者表示过去将来或者虚拟语气，相当于“将会”，如：
What would you do if you were 5 years old? （如果你5岁，你将做什么？）

Answer 2

填could
What could you do when you were five years old?
翻译：
你五岁的时候，你可以做什么？

Answer 3

MODAL

would，这里考察情态动词

1.(表示曾经相信、希望或期待)将，将会
2.(表示曾经打算)将，将会
。。。。。。。

Answer 4

What would you do when you were five years old?

Answer 5

what do you do when you were five years old?