While I_______ a detective story, someone_______ at the door．

It is widely believed that China has been into a more prosperous and advanced country in the last century.

.Three-fourths of the buildings______.

Can I help you —Yes, please. I want to ______some fruit.

(2014·南通第二次学情调研)—In case anyone ________come in my absence，tell him I will be back soon.—Sure，I will.