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 lookout for) 密切注视