单项选择题
—Is Mary in7 —No, she's out and won't be ______ till nine o'clock.
单项选择题 —Did you see Jack at the wedding party —No, he ______ by the time I ______ there.
单项选择题 Children are usually ______ about things around them.
单项选择题 How beautifully she sings! I have never heard ______.
