事態は急を要するので一刻も待てないと彼は言った。
He said that the matter was urgent, and that there was not a moment to lose.

屋根にいく階段は狭くて急でくらいです。
The staircase leading to the rooftop is narrow, steep, and dark.

この川の流れは急だ。
The current of this river is rapid.