"open your mouth" in Chinese (Simplified)
张开嘴巴
Definition
把嘴唇张开，使嘴巴不是闭着的，通常是为了让别人检查、说话或吃东西。
Usage Notes (Chinese (Simplified))
常用于医生或牙医检查时，也可以让某人说话或唱歌。在非正式场合，有时用来鼓励害羞或沉默的人开口。
Examples
Please open your mouth so the dentist can check your teeth.
请**张开嘴巴**，让牙医检查你的牙齿。
The doctor said, "Open your mouth and say 'ah'."
医生说：“**张开嘴巴**，说‘啊’。”
He couldn't open his mouth because he was too nervous.
他因为太紧张，没法**张开嘴巴**。
You need to open your mouth wider for that big bite!
你得**张大嘴巴**，这样大口咬下去！
Don’t be shy—just open your mouth and say what you think.
别害羞——大胆**张开嘴巴**说出你的想法。
When the teacher asked a question, not a single student would open their mouth.
老师提问时，没有学生**张开嘴巴**回答。