***Not a teacher***
'Think about' is used when I am actually deliberating or cogitating about something, and expresses something of a process. 'Think of' does not draw attention to the process of thinking, but often refers to an instantaneous thinking of something
e.g.
"When I think about the exam, I get very nervous".
- draws attention to the process of my deliberate thinking and suggests it is over a period of time (even if it is only a brief period).
'When I think of the exam, I get very nervous'
- does not draw attention to the process. This could refer to whenever the thought pops into my head for a second (but could also refer to when I spend time considering the exam), whereas 'think about' suggests that I am in the process of deliberately thinking about it for a while.
So to summarise, 'think about' suggests a deliberate process is involved, whereas 'think of' does not say anything about process and is probably more likely to refer to instantaneous thought, which may be spontaneous and not deliberate.
Another use is:
'What did you think of the game' when asking for an opinion on something is used often, and I don't think 'What did you think about the game' would be quite right in this case - although this may just be a personal preference.
Ade
