—People near the lake didn't allow them to________ a factory so as not to pollute the water.
A:look up
B:put up
C:take up
D:set up
读“世界部分区域图”,回答下列问题。
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某工程的工序流程如图所示(工时单位:天),现已知工程总时数为10天,则工序c所需工时为( )
手持一个凸透镜在室内白墙和窗户之间移动(离墙更近些),在墙上能看到( )
若sin20°=cos(α+25°),则tanα=____.