—I have trouble______ math; I failed the math test again.
—Don’t worry. I can help you.

(单选题)By walking to and from school, children can learn ________. (单选题)Who are encouraged to take part in the programme of “Walk to (单选题)What would Bill probably say at last? (单选题)Three days before graduation, Bill asked Mark to talk becaus (单选题)At Bill’s home, they didn’t ______. (单选题)Which of the following is NOT true? (单选题)When Bill fell down on his way home, Mark ______. (单选题)30.（ ） (单选题)29.（ ） (单选题)28.（ ）