In our school ______ some grass. It's green.

There are

there is 么，没看懂。

there is 为什么不用there are 呢 因为它是不可数名词 所以用there is

there are 因为SOME修饰了GRASS表示草在这里是可数的，是复数．所以应该用 ARE

there is

grows 长着
这是一个倒装句,正常语序是Some grass grows in our school. It's green.
又如:
This district grew cotton on a large scale.
这个地区过去大量种棉花。

there is因为后句是：it's.所以这里grass是不可数名词，另外some可以修饰不可数名词。

chq0621说的对！grows
补充一点：这里是用主动表被动
there is也没错，只是太平庸了！

赞成 grows

there is
因为 grass 是物质名词，不可数

there are