【单选题】Mike is ______, but his brother Sam is much ______.
【单选题】Mike is _____ than his friend Sam.
【单选题】干贝体表有( ),不能食用,泡发时必须去除。
【简答题】Anda dapat menarik beberapa ______ (总结) di sini
【简答题】封面图片中能分辨出哪两个字母?它们是由哪种蔬菜拼出来的?
【单选题】单项选择。 — Hello! Is Sam? — No, is Mike. [ ]
【单选题】Who is , Tom, Sam or Mike?
【简答题】从光密介质到光疏介质,当sini 1 >n 2 /n 1 时发生全反射.作为一种处理方法,我们仍可在形式上维持折射定律n 1 sini 1 =n 2 sini 2 .这时sini 2 >1,可认为i 2 是个虚折射角,它的余弦也为虚数: 试利用菲涅耳公式证明此时|r p |=1,|r s |=1.