—Is this your brother?[—______.
He _______ go out with his parents, but now he _______ staying at home alone.
----How do you like the two pairs of shorts? ----They don’t fit me well. They are _______ too long _______ too short.
________ my surprise, the twins have nothing _______ common.
---Do you know sound travels very fast? ----Yes. But light travels _______ sound.
Paper-making is one of _______ of ancient China.