back-breaking
/ˈbækˌbreɪkɪŋ/adjective
1- (especially of manual labour) physically demanding（尤指体力劳动）累人的, 繁重的：
a day's back-breaking work.
一天的繁重工作。
1.1
- (of an inefficient tool) tending to make a task difficult（无效的工具）帮倒忙的：
put away those old back-breaking hand tools.
把那些只能帮倒忙的旧工具收起来。