be at one's wits' end
不知如何是好
A：Does he know that he's already at his wits' end?
A：他知不知道他已经山穷水尽了?
B: I think he's realized that. But he's still whistling in the dark by putting up an act.
B：我想他已经意识到了，但他仍装腔作势为自已壮胆。
A: He might be driven up a wall. You should handle your relation with him with kid gloves.
A: 他快被逼得走投无路了，你应该以温和的手段对付他。
B: But when I noticed that he was left in the cold, I couldn't help wanting to help him to get out of the situation.
B: 但当我看到他已是孤家寡人的时候，我又不由自主地想帮助他摆脱这种状况。