at strain的用法和样例：
例句
- He is working hard at this thesis.
他正在努力地撰写论文。 - I study my English lesson very hard at school.
在学校我很努力地学习我的英语课。
词汇搭配
- strain at a gnat 谨小慎微
- strain at 用力
- strain at the leash 牵扯皮带
- strain at something 使劲拉某物
- strain at a gnat and swallow a camel 拘于小事大事糊涂...
