Вопрос по английскому языку:

He has a toothache that's ...... he can't eat sweets.
A)when B)why C)who

The ..... is missing.
A)box's top B)box top's C)top of the box

Our parents love ..... very much.
A)we B)ours C)us

There are fifteen ....... in the classroom.
A)child B)childrens C)children

You mustn't ....... late for school again.
A)being B)to be C)be

This book is not ...... . It's Sue's.
A)mine B)me C)her

Do you know how ....... this laptop?
A)used to B)to use C) to used

You ...... call him now. You can do it later.
A)not have to B)haven't to C)don't have to