题目

根据短文内容及首字母提示，在空白处填写合适的单词，使短文完整，连贯。Starting high school is a great e【1】 for every teenager．Whether you are coming from the countryside or the city，there are many things about high school that are d【2】 from your old school environment．You will experience many changes．You will face being in a new school，m【3】 new friends in an unfamiliar class and getting to know new teachers．These new teachers will usually have higher academic（学术的） level t【4】 your junior high school teachers．They want to he19．下列四组线段中，不构成比例线段的一组是（　　）A．1cm，2cm，3cm，6cmB．2cm，3cm，4cm，6cmC．1cm，$\sqrt{2}$cm，$\sqrt{3}$cm，$\sqrt{6}$cmD．1cm，2cm，3cm，4cm