(甲)和(乙)都, 既...又..., 不但...而且...

同时，a会假设b仍然在做同样一件事情。从一开始，两者都在假设这个类型化的相对性。

一开始，A和B都假定了这种交互作用类型。

take one's courage in both hands

make both ends meet

igh in both output and quality, but low in production cost

boost(increase, raise，or step up) production both intensively and extensively

resembly both vacuity and repletion

be small at both ends and big in the middle; a few at each extreme and many in between

be ready to both serve as an offical and be one of the common people

competent to work both at the top and at the grass roots