He opened his mouth and sent forth a stream of noise.

他张开嘴，发出一连串嗓音。

《牛津词典》

The next morning, when he opened his mouth to say "Good morning", nothing came out but a croak.

第二天早上，他张嘴想说“早上好”时，发出的却是呱呱声。

youdao

He opened his mouth to speak.

他张开嘴正要说话。

youdao

He opened his mouth, clenched his teeth over the handle, and pulled it up for about eight seconds.

WSJ: At These Olympics, It Helps

He stood in front of her desk, and a second before he opened his mouth to speak Vivian realized who he was.

NEWYORKER: Temporary

He looked around the room, as if for more food, and when he opened his mouth wide Titania thought he was going to shout or cry.

NEWYORKER: A Tiny Feast