cycle
英 ['saɪk(ə)l]
美['saɪkl]
	    - n. 循环;周期;自行车;整套;一段时间
 - vt. 使循环;使轮转
 - vi. 循环;骑自行车;轮转
 
英英释意
- 1. an interval during which a recurring sequence of events occurs;
 - "the neverending cycle of the seasons"
 
- 2. a series of poems or songs on the same theme;
 - "schubert's song cycles"
 
- 3. a periodically repeated sequence of events;
 - "a cycle of reprisal and retaliation"
 
- 4. the unit of frequency; one Hertz has a periodic interval of one second
 
- 5. a single complete execution of a periodically repeated phenomenon;
 - "a year constitutes a cycle of the seasons"
 
- 6. a wheeled vehicle that has two wheels and is moved by foot pedals