420.keep a close watch on (=keep a sharp lookout for)密切注视
421.keep……to oneself (=keep secret)不告诉别人
422.to (the best of) ones knowledge据……所知
423.at large (=at liberty， free)在逃，逍遥法外
at large (= in general) 一般来说，大体上
at large (= at full length; with details) 详细地
更多信息请访问：
424.lean against(背)靠着……
425.at least 至少；at most 至多
426.(not) in the least 一点(也不)，丝毫(也不)
427.at ones leisure 在……有空的时候
428.lend itself/themselves to 适合于(某用途)
429.at length (=after a long time，at last) 终于
at length (=in detail，thoroughly) 详细地
430.go to any length 想一切办法，尽一切力量
431.be liable to (=be subject to) 易于……的，应受(罚)
432.be liable for 对……应负责任的
433.lie in 在于
434.in life 一生中
435.for life 终身
436.in the light of (=considering;taking into account) 考虑到，根据
437.throw light on (=make clear，explain) 使……更为清楚，提供线索，阐明
438.in line with (=in agreement with) 符合，一致 439.long for (=want very much) 渴望，希望得到
440.for long 很久，很长时间(否定句，疑问句中)
441.before long (=soon) 不久，过了不久以后
442.in the long run (=in the end ) 从长远来说，最后；in the short term (从短期来说)
443.(be) at a loss 不知所措
444.major in 主修(某课程)
445.as a matter of fact 实际上，事实是
446.by all means (=at all costs) 不惜一切
(=certainly) 当然行；by means of 用……；by no means 完全不，决不
447.on memory of 为纪念……
448.on the mend (=in the process of recovering) 好转，在康复中
449.mention sth. sb. 向某人提起某事
450.at the mercy of (=in the power of ) 任……摆布，在……支配下