（ )the end of last week he had finishhed one-third of the work 杂填?填介词
问题描述：
（ )the end of last week he had finishhed one-third of the work
杂填?填介词
答
BY
答
At
答
by
直到上周末他已经完成了三分之一的工作.
答
By
by the end of last week
到了上个周末