1 . 打算盘也被称为珠算。先熟背一个简洁的公式，通过这个公式，加、减、乘、除的运算都可以简化成移动算珠。（汉译英）

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2 . That was the office _________ they could look out to the sea.

A．from which

B．from where

C．that

D．which

3 . The use of genetic engineering should be restricted to just those cases _____ the health of the mother or her baby is threatened.

A．in which ​​​

B．how

C．of whom

D．why