21.in a nutshell--in a few words来源：考试大

　　22.from top to bottom--completely;entirely

　　23.take the plunge--enter with sudden decision upon an unfamiliar course ofaction

　　24.on the tip of one's tongue--unable to be recalled来源：考试大

　　25.cheer up--feel happy;stop being sad or discouraged;become hopeful

　　26.hold off--postpone;delay来源：考试大

　　27.on cloud nine--a state of perfect happiness来源：考试大

　　28.back out--withdraw from an undertaking

　　29.grin and bear it--be as cheerful as possible in pain or trouble;do something without complaining

　　30.turn out to be--come to be;prove来源：考试大

　　31.bite off more than one can chew--attempt something that exceeds one's ability

　　32.in the air--uncertain来源：考试大

　　33.get hold off--find a person so you can speak with him来源：考试大

　　34.learn the ropes--acquire thorough or special knowledge of a job

　　35.tear oneself away from--depart with great reluctance;force oneself to leave

　　36.tie up--engage or occupy completely来源：考试大

　　37.touch on--mention a subject briefly or casually

　　39.see to it--take care;take the responsibility;make sure

　　40.get along with--live or work in harmony with