张口

例句：

1. 1. 他张口就问：“你今天过得怎么样？”
   He opened his mouth and asked, "How was your day?"
2. 2. 她张口欲言，却突然沉默了。
   She opened her mouth to speak but suddenly fell silent.
3. 3. 他张口结舌，不知道如何回答。
   He opened his mouth and stuttered, unsure of how to respond.