The volunteers at the airport offer --- heavy luggage for the passengers.
问题描述：
The volunteers at the airport offer --- heavy luggage for the passengers.
A.carrying B.carry C.carried D.to carry
答
D
.to carry不定式做宾语,在时间上指将要发生；而动名词carrying做宾语表示经常的行为,错误；其他两个都的谓语动词形式,错误.