Usages of kāi
你 可以 开 门 吗？nǐ kěyǐ kāi mén ma?
Can you open the door?
他 正在 开 门。tā zhèngzài kāi mén.
He is opening the door.
门 开 着， 护士 站 在 外面 等 我。mén kāi zhe, hùshi zhàn zài wàimiàn děng wǒ.
The door is open; the nurse is standing outside waiting for me.
我 刚才 忘记 带 书 了， 他 帮 我 开 门。Wǒ gāngcái wàngjì dài shū le, tā bāng wǒ kāi mén.
I just forgot to bring the book; he helped me open the door.
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