Our homework is figuring out the area of the cross section of a solid. 我們留的作業(yè)是求幾何體橫截面的面積。
If we look at a cross section of a water wave, we may see that the wave form repeats itself at regular intervals. 如果我們觀(guān)察水波的橫截面，我們會(huì )看到波形是按一定的間隔重復的。
滬公網(wǎng)安備 31011502000490號
電信業(yè)務(wù)許可證編號：滬B2-20190700
