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.
54+57 =____
实验表明,磁体能吸引1元硬币,对这种现象解释正确的是( )
如图是一平放的活植物根尖,另将2个琼脂块A、B置于如图位置.以下说法正确的是( )