The traffic rule says young children under the age of four and ____ less than 40 pounds must be in a child safety seat.
It is _______ he had to send his brother to hospital _______ he was late.
September 11, 2001 is the day ______ we will never forget.
How do you _______it and what should you ________it?
-Do you know our hometown at all?-No, this is the first time I _______ here.
-Have you finished your experiment report, Jane?-Oh, my God. I’ve _______ forgotten all about that.