I just read this: 你明天有没有事？ Can somebody tell me what it means? Also, if I want pronounce this sentence in 普通话, then must I use 儿化 in the word 事 or is it optional? I know that 儿化 is necessary in some words in 普通话, for example 一会 and 一块. But in some words like 一点 (我会说一点英语。) it is optional. If you don't do 儿化 in 一点, you will not lose marks on your putonghua test in China.