本 Headway - 中上級 - 日常英語（ユニット9）

to make a low sound that often expresses pain, grief, or disappointment

to make a deep, low sound, typically expressing pain, despair, or disapproval

experiencing great sadness, shock, or disappointment

to accept something to be true even without proof

to be understandable in a way that is reasonable

treating everyone equally and in a right or acceptable way

an activity or situation that does not produce any benefit or value, and instead consumes time and resources that could be better utilized elsewhere

to stop being harsh or strict with someone

impossible or very hard to control

an uneasy feeling that we get because of our own or someone else's mistake or bad manner

causing slight anger

to feel regret or disappointment in oneself for a past mistake or missed opportunity

to start becoming a source of trouble or worry