tist was born poor,poorhe remained all his life

下列句中“于”的用法与“其势弱于秦”中“于”的用法相同的一项是（ ）

Some young people in America are expected to leave ______ could be life’s most important decision—marriage— entirely up to luck

The old man made ______ clear that he wouldretire soon.

— How long _____ you _____ in the country with your grandparents, Henry?— About four weeks. I’ll return as soon as school starts.[ ]