用法:
1 [U] state of being obsessed 牵挂; 惦念; 著迷; 困扰:
His obsession with computers began six months ago. 他半年前就迷上了计算机了.

用法:
2 [C] thing or person that obsesses; fixed idea that fills the mind 萦绕於心的事物或人; 强迫观念:
He has many obsessions. 他有许多事耿耿於怀.

• for the purpose of(for the sake of)
• for the world(for the whole world, for all the world)
• for want of(from the want of, from want of)
• for want of(in want of)
• for years(for one's years)
• for(because of)
• for(for all)
• for(from, of)
• for(in favour of)
• for(in)
• for(since)
• forbid doing sth(forbid sb to do sth)
• forceful(forcible)
• forego(forgo)
• forget doing sth(forget to do sth)
• forget him(forget himself)
• forthcoming
• forward(well up)
• free from(free of)
• free(freely)
• frequently(often)
• from first to last(through and through)
• from one's heart(in one's heart)
• from one's mind(in one's mind)
• from … through(from … to)