The students couldn't help ______ when they heard the joke.
A. to laughB. laugh C. laughing
Do you know ______ this word?
A. what to spell B. how to spell C. to spell
Be quiet! The babies ________.
A. sleepB. are sleepingC. slept
He asked me _____ I would like a cup of tea.
A. that B. what C. If
找出下列英文单词所对应的中文意思。