all these three words have the meaning of "doing sth", but there are also difference: 1 meaning "正" mainly about the time, "在" mainly about the status, and "正在" covers both time and status, like ---在干吗？---我在做作业呢。 ---what are you doing? ---i'm doing homework. ---在干吗？能来一下吗？ ----我正做作业呢！ ---what are you doing? can you come now? ---i'm doing my homework! here, "正" emphsis on "i have sth to do at the moment now", of course u can use "在", but not so good as "正" here 2 grammar when you use “正", you can not merely use "正+verb"， while it is ok in "在" and ”正在“ ---你在做什么？ ---我在做作业。 ok ---我正在做作业。 ok ---我正做作业。 no----我正做作业呢！ Ok --- you need to use "正+verb+呢/着" 3 在can not be followed by "从"（from）， while 正 and 正在 is ok 他正从学校赶回来。OK 他正在从学校赶回来。OK 他在从学校赶回来。NO 4 在can be used to mean the actions are done again and again or lasts quite long, while 正 and 正在 can not. 正在做作业. doing homework now OK 一直正在做作业 NO ---一直在做作业。 ok you can see when 正在and 在 can only be used in "doing sth now", but not "doing sth all the time"

ok...i should be happy someone is intersted in it...

lady, i think this is my translation from my blog....

sorry u meet the origin translator

杰克船长 haha, i love that movie 加勒比海盗 and 杰克船长's 兰花指~~

this is a tough question i agree and i agree more than u should post it on economic website it is more suitable for a topic of an essay than a mere question

万事如意 an old chinese saying used mainly in festivals wish sb everything well the same usage are those like 一路顺风 wish u a safe travelling 吉祥如意 good futune are always with u 事事顺心 everything goes like u wish

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