Now most families have only one child _____ our country’s one-child policy.
—Is this ________ key, Tom? —No, that one is ________.
.—Is this your book, Jane? —_______. Thank you!
—I like this sweater. I’ll take it. —Please pay for (付款) it. It’s 100 yuan.
—Do you like ball games? —Yes. They are very fun.
—I have a birthday party this evening. Are you free? —Yes, I am.