Yesterday afternoon John and I were walking along a road
where we heard someone shout "Help! Help!" He was in __1__
a lake, about a hundred feet from the shore. There was a __2__
small boat nearby. We knew immediately what happened. __3__
He had fallen out of the boat and could not swim good enough __4__
to reach it or to get to the shore. As we ran towards the lake I
saw him sunk, and I was certain that he would drown. But in __5__
a moment his head appeared again. Quickly John took out his __6__
shoes, jumped into the water and started swimming toward
the drowned man. He reached him just as the man went down __7__
again. He was close enough as to stretch out his hand and try __8__
to take hold of the man's clothes or his hair before he sank.
But the man threw out his arms in fear, caught John across the __9__
neck, and began to draw him down under the water. John
fought to keep his head above the water and at the same time
tried to swim toward the boat, pulled the man with him. __10__

答案及解析:
1. where—when

2. a lake—the lake
据上下文判断，这是指离海边唯一的湖泊，因此用定冠词

3.在happened前加had

4. good—well
副词well修饰swim

5.sunk—sinking
现在分词表示正在进行的动作

6. out—off

7. drowned—drowning
drowned意味着此人已经被淹死了，drowning表示正在进行，快要淹死了
8. 去掉as
直接由to stretch作状语

9. across—around
across意味“穿过”，即“穿过他的脖子”，意义不通顺。改为around即为“抱着他的脖子”，合乎逻辑和本文意义

10. pulled—pulling