单选题 To his great surprise, he found under the tree _____ ants swarming from a small hole in the damp ground up to the tree trunk, each carrying a burden several time heavier than itself.无

A、 a series of
B、 a host of
C、 a range of
D、 a variety of

【正确答案】 B

【答案解析】句意：令他十分惊讶的是，他发现树下一大群蚂蚁从地上潮湿的小洞里爬到树干上，每只蚂蚁的负重都是自己体重的几倍。 a host of许多，一大群。