You may have noticed that there is no generic way to say yes or no in Chinese. The simplest way to answer a question with yes is to repeat the verb or adjective from the question.
你喜欢不喜欢狗?
Nǐ xǐhuān bu xǐhuān gǒu?
Do you like dogs?
喜欢。
Xǐhuān.
Yes.
她们忙吗?
Tāmen máng ma?
Are they busy?
忙。
Máng.
Yes.
To say no, add 不 before the repeated verb or adjective.
你要不要咖啡?
Nǐ yào bu yào kāfēi?
Do you want coffee?
不要。
Bú yào.
No.
你去美国吗?
Nǐ qù měiguó ma?
Are you going to the US?
不去。
Bú qù.
No.
Add 在 before a verb to show that something is happening right now.