Once you have finished the design, you may have a whole week.
A.off
B.down
C.in D.up

The sun must be made of lighter stuff than the earth. If the earth were______, it would weigh four times as much.A．biggerB．smallerC．as biggerD．as big as the sun 点击查看答案

My American friend knows my problem because I()my ideas with him.A.have changedB.changedC.have exchangedD.exchanged

A.
A.have
B.changed
C.have
C.exchanged

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