[clarity]

here is another question
It has been____used for entertainment in China since the 7th century.
A.usually B commonly

which one is right .i think both but the key is usually. i do not know why. anyone can tell me the diference. thanks in advance.

[susan53]

Both are possible, though personally if I had to go for one of the two, I'd choose commonly.

Usually refers to the frequency of use - and to me gives the impression that whatever we're talking about (incidentally, it's much easier to analyse the use of words if you give a full context) has been used more often for entertainment than for any other use. I'd see the full context as being something like :

The XXXX can be used seriously or for entertainment. Since the 7th century in China, it has usually been used for entertainment.

Notice that I've changed the order of the words here. The sentence sounds strange to me as you've quoted it, but again, that may depend on context. In particular, with usually and used together, the repetition of the sounds /juz/ is a bit clumsy.

Commonly also refers to frequency, but has the added idea of something being geographically widespread. The definition for common given in the Longman Dictionary of Contemporary English is "found or happening often and in many places". This to me seems much more suited to the sentence you quote, as well as avoiding the clumsy repetition of sounds. Another possibility would be generally.

[clarity]

thanks a lot