DUO

duo(1)

多 = many, (to what extent?)

The meaning 'to what extent' is a function, rather than a meaning; it's occurance is not to be translated as 'to what extent', but rather as 'how...'

多少 = duo(1)shao(-) = how much?

多长时闻了 = duo(1) chang(2) shi(2) jian(1) le(-) = how long?

你洗衣服多长时间了?  = Ni(3) xi(3) yi(1) fu(-) duo(1) chang(2) shi(2) jian(1) le(-)? = How long did you wash clothes?

In Chinese, 'how long', in some instances, has to be expressed as:

多久 = duo(1) jiu(3) = how long?

你学习中文多久了? = Ni(3) xue(2)xi(2) zhong(1)wen(2) duo(1) jiu(3) le(-)? = For how long did you learn Chinese?

The 多久 combination is used for definitely long periods, and for states that are ongoing; the 多长时间 combination is used for shorter events that have already ended.

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