a) The person who stole the painting must have been tall.

-> Whoever stole the painting must have been tall.

b) I don’t mind what you do, but don’t tell Jane I was here.

-> Whatever you do, don't tell Jane I was here

c) What on earth is the time?

-> Whatever is the time? 

d) I’d like to know why you told me a lie.

-> Why ever did you tell me a lie?

e) Every time I go on holiday, the weather gets worse.

-> Whenever I go on holiday, the weather gets worse.

f) Tell me where you have been!

-> Wherever have you been?

g) How on earth did you know I was going to be here?

-> However did you know I was going to be here?

h) I won’t believe you, no matter what you say.

-> Whatever you say, I won't believe you.