There is _______ “f” and _______ “u” in the word “four”.
No one knows ______ the task will last. What a pity!
During the busy traffic time, some people prefer to ride bikes because it’s much______.
—I often have hamburgers for lunch. —You’d better not. It’s bad for you ______ too much junk food.
—Where is Jack? I haven’t seen him for a long time.—He ______ HK with his family. I think he is having a wonderful time there.
High school ______ covers a lot, including Chinese, Math, Geography and so on.