发狠[fā hěn ]
词典make a determined effort：发愤；矢志力行；切切实实；发狠。
词典发狠是什么意思
词典be angry：嗔；有气；怫然；发气。
词典turn angry [wrathful]
发狠[fā hěn]
（下决心） make a determined effort:
例：他们一发狠，三天的任务一天就完成了。
With a determined effort, they finished the three-day task in a single day.