1. 去掉yet 2. 去掉were 3. at 后面加an 4. us-ourselves 5. helplessly-helpless
6. swimming-swim 7. treat-treated 8. or-and 9. other-others 10. when-since
1. 去掉yet 2. 去掉were 3. at 后面加an 4. us-ourselves 5. helplessly-helpless
6. swimming-swim 7. treat-treated 8. or-and 9. other-others 10. when-since