问题
选择题
When he saw a little boy ______ in the river, he took off his shirt and jumped into the water.
A．struggles
B．struggling
C．to struggle
D．struggle
答案
答案：B
see sb doing sth “看见某人正在做某事”句意为“当看到小男孩在河水中挣扎时，他脱掉衣服跳进水中。”所以选B。