You can use delta minus, delta plus.

你可以用△+，△

麻省理工公开课 - 固态化学导论课程节选

I can't give it what it wants," know that when you're writing code and the problems that will remind of this, if you absolutely have to kill your program, you don't have to close the window, CTRL+C reboot crazy stuff like that, generally you can hit CTRL+C and it will just abort the program right where it is, in case you ever get trapped in some awkward situation.

我不能给它所要的“,当你在写代码时，程序将,提醒这个问题，如果你不得不,关闭这个程序，你不需要关闭这个窗口，重启像那样的疯狂举动，通常你可以敲,它将会在这个地方终止那个程序，假使你陷入了尴尬的处境。

哈佛公开课 - 计算机科学课程节选

You can verify, in this simple example, that A + B is the same as B + A.

在这个例子中还可以验证,A + B = B + A

耶鲁公开课 - 基础物理课程节选

There's a very natural quantity that you can call A + B.

有一个很自然的量可以记做 A + B

耶鲁公开课 - 基础物理课程节选

Now, we are done because now we can ask how high does it go, and you go back to your y of 1 is 15+10-5, which is what?

现在问题解决了,因为我们可以算出,最高点的高度,你回到这个式子,求出y=15+10-5,是多少

耶鲁公开课 - 基础物理课程节选