1. 一点儿

"一点儿"(yī diǎnr) means "a little bit". You can put it behind a verb, adverb, or adjective. "儿"(ér) does not have an exact meaning. It's just a kind of language habbit.

2. 不要……

"不要……"(bú yào) here is commanding, meaning not "don't" instead of "don't want".

3. 打开

When "打开"(dǎ kāi) used as a term, it means "to turn on". "开"(kāi) itself can be a verb or an adjective. For example, "开空调"(kāi kōng tiáo) ("开" as a verb), "空调是开的"(kōng tiáo shì kāi de) ("开" as an adjective).

4. 了

"了"(le) in "你感冒了"(nǐ gǎn mào le) can be used after a verb to indicate that the action has been finished or has already been a certain state.