weak at的用法和樣例：
例句
- "How do you feel?" "Fine, really. A bit weak at the knees but that will soon pass."
"你感覺(jué)怎么樣？""還好，真的。只是有點(diǎn)發(fā)抖，一會(huì )兒就過(guò)去了。" - The shock make me go all weak at the knee.
這件事把我嚇得兩腿發(fā)軟。 - The shock made me go all weak at the knees.
這件事把我嚇得兩腿發(fā)軟。
