Optical invariant

optical ['ɑptɪkl]

adj. 视觉的，视力的;眼睛的;光学的;

optic光学的 + al 表示属于...的、具有...性质的、如...的 → a.眼的；光学的

invariant [in'vεəriənt]

adj. 无变化的，不变的; n. 不变式，不变量;

That's fantastic!

真了不起！

Help! I'm being killed.

救人呀！我要被杀死啦！

On our way home that night I looked down and saw that the necklace was not around my neck any more. I told Pierre. We rushed back to the palace and looked for it.We asked everyone there if they had found a necklace, but without luck. We couldn't find it;

那天晚上在回家的路上，我低头一看，发现项链不再挂在我的脖子上了。我告诉了比尔。我们马上赶回王宫去寻找。我们询问了那儿的每一个人，问他们是不是拾到了一条项链。可是，真倒霉。我们找不到那条项链；它丢失了。