题目

1. Thank you for _____­­­­­­­­­­­­______ (help) me with my English. 2. Many children are ________ (interest) in ________ (collect) stamps because they think it _________ (interest) to collect them and they can learn a lot from it. 3. You have been _________ (play) computer games for a long time. It is bad for your eyes. 4. Our teacher told us some _____________(different) in food between ___________(west) countries and China. 5. In China people don’t eat ___________ (separate). They usually order food to share. 6. English is very ______ (use). So we should try our best ____已知函数， 有如下四个命题：①点是函数的一个中心对称点；②若函数表示某简谐运动，则该简谐运动的初相为；③若，且，则（）；④若的图像向右平移个单位后变为偶函数，则的最小值是；其中正确命题的序号是________ _______．