---It’s time to sleep, Daniel.---Oh, Mum, I won’t go to bed _____ I finish my homework.
—Would you mind opening the window? —____. Look at the heavy haze (霾) outside.
It’s ____ useful book. And ____ book is popular with students.
—Is your headache getting _______? —No, it’s worse.
—Which is your new neighbor, Liu Hua? —The man _______ T-shirt is red.
—Do you know _______ the Capital Museum? —Next Friday.