她开始用钢琴演奏那首民歌.She struck up a folk melody on the piano.应观众再唱一曲的要求, 他清唱了一首民歌.For an encore, he sang an unaccompanied folk song.她在哼一首我以前从未听过的民歌.She is humming a folk song that I never heard before....
把它们相加再除以5就是平均数,明白吗?Add them together, divide by five, and you've got the average. Okay?量一下温室的建筑面积再将它除以6。Measure the floor area of the greenhouse and divide it by six.230厘米除以22厘米等于10.45厘米。230cm divided by 22cm is 10....