puzzle困难: difficulty; difficult; hard; ...的: 4次方是 The fourth power of 2 i ...问题: question; problem极其困难的问题: an exceedingly difficult problem繁难的问题: knotty problem下载手机词典可随时随地查词查翻译关注微信公众号:chachacidian,回复:困难的问题,即可在微信中查询翻译