如图所示，不计容器本身的重力，容器的底面积相等，倒入等高的不同种液体时，容器对桌面的压强相等，则容器底部受到液体的压强最小的是（　　）

用托盘天平不能直接测量出一粒芝麻的质量，是因为这一粒芝麻的质量（　　）

根据句意和首字母提示，完成句中所缺单词
①We should brush our____ (tooth) every day.
②—What’s Jane doing? —She’s b____ her sister.
③ What is she doing for v____ ?
④—How do you come to school?  —I usually ride a b____  to school.
⑤ I want to s ____ an e-mail to my aunt.