411.invest in 投 资
412.be involved in(=become connected or concerned)卷入，参加
413.by itself(=alone，without help)单独地，靠自己
414.in itself 本身;of itself 自发，自然
415.be jealous of 妒 忌
416.jump at(=to be eager to accept)抢着接受
417.jump on(=scold，tell of)叱责
418.junior to sb. 年纪较…轻，职位较…低.
419.(be)keen on 喜爱，渴望
420.keep a close watch on(=keep a sharp look out for)密切注视
421.keep…to oneself(=keep secret)不告诉别人
422.to(the best of)one’s 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
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 one’s leisure 在…有空的时候
428.lend itself themselves to 适合于(某用途)
429.at length(=after along 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
