单项选择题In my opinion, the first thing ()is what tools we should use.
单项选择题This is one of the main ways ()a business learns what customers want.
单项选择题Our advertising rates are()size and location.
单项选择题Sometimes it()over half the total time spent on a research problem.?()
A.takes upB.takes offC.takes on
单项选择题Born into a rich family, he has no idea of () to be a poor man