[LDOCE,柯林斯,牛津,stackexchange] 2加3。把2和3加起来。起来: up. Add up means the same as add. add up to = amount to. 想象下一袋袋麦子up up.

If you add 2 and 2 (together), you get 4. Two plus two is four. One plus one is two. One and one is two. [注意add, and, plus] Fluent English speakers routinely say it both ways, "one and one is" is significantly more popular, but "one and one are" is still common.

1+2+3=800. If facts or events do not add up, they make you confused about a situation because they do not seem to be consistent.
Ross: Oh yeah, we're uh, yeah we're not together. (He starts backing out of the store.)
The Salesman: Ohh, okay. (Laughs.) Something didn't quite add up there. (Ross stops, walks back to talk to the salesman, and in the process pushes Rachel up against a wall.)
Rachel: Ross!
Ross: What's that supposed to mean?
Rachel: Ross!
The Salesman: Well you, her, I mean, she's very… you know. And you're like… you know.

12+23+35=69. If something that someone has said or done adds up, it is reasonable and sensible.

"And I love you," Leonard added.
Don't forget to add in the cost of your time.
The chapel [小教堂] was added on to the church much later.
This will add to his growing reputation.

A grammar school is one of several different types of school in the history of education in the United Kingdom and other English-speaking countries, originally a school teaching Latin [拉丁文], but more recently an academically oriented [面向] secondary school. A secondary school describes an institution that provides secondary education and also usually includes the building where this takes place. Some secondary schools provide both lower secondary education (age 12 to 15) and upper secondary education (age 15 to 18).

不要因此就说都不敢话了。