at this week ,on this week ,in this week 之中用哪个?有何区别?

题目

at this week ,on this week ,in this week 之中用哪个?有何区别?
另外,＂Our company developed a new umbrella last month."中的＂developed"用＂made＂还是＂created＂代替比较好?

答案

at this week 和on this week 是错的. in this week是在本周的意思.
develop这里用created 好一些,是开发、研制的意思. made是制造,你的句意肯定不是找了一种新伞,而是研制了一种新伞.