Our mother earth gives us ________ we need in our daily life.
--- Did I lock the door when I went out? --- Yes, you did. I saw you _____ it.
---You have to work very hard in your job, don’t you? ----Yes, but I don’t mind that. I _____ hard.
--- I don’t know ______ my telephone number. --- Through a friend of mine.
---David,is that man your Chinese teacher? ---It___________ be him.He’s having a meeting.
---Why weren’t you at the meeting? ---I ____for a long distance call from my sister in America.