is he doing his homework?

0I sometimes am confused as to how to answer that kind of questions as above. Help02br
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00Q: 01u00Is he doing02u00 his homework?02br
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00A: Yes, he is doing his homework.02br
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00Q: 01u00Is the pen working02u00?02br
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00A: Yes, it works.02br
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00I know the verb forms in the 1st and 2nd sentences are not exactly congruous in terms of its functional ramifications, but sometimes, I think just the present form will suffice and more acceptable than the present contiuous form when being asked with the questions in present continuous.02br
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00Also, can the word "homework" mean a "homework" in general sense and can function as 01u00a sort of mass noun02u00 00here like homeworks in Math, History, etc., all inclusive? 02br
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00Can the colored phrase can be changed to "sort of a mass noun"? 0-