选出句子的正确答语。⑴ What are the birds doing? {#blank#}1{#/blank#} A. There are twenty-one birds.
⑵ How old are you? {#blank#}2{#/blank#} B. Yes, I do.
⑶ Are there any toys in the box? {#blank#}3{#/blank#} C. They are singing happily.
⑷ How many birds can you see? {#blank#}4{#/blank#} D. No,there aren't.
⑸ Do you like cars? {#blank#}5{#/blank#} E. I'm ten years old.