绷着脸

• not have a word to throw at a dog
• with a straight face

例句

1. 我看见老板绷着脸在办公室里走来走去。
   I saw the boss going about the office with a long face.
2. 我摔倒时，那个小男孩并没有笑，他只是绷着脸站在那里看看我。
   The little boy didn't laugh when I fell down. He just stood there watching me, as sober as a judge.