.–Have you ________ to Shanghai–Yes, I___________ there to see my sister last year. She has ____________ Pudong for 2 years.

下列词语中有错别字的一组是(　　)

do the washing-up. Jack, would you pleasedo the floors—_______.

The students in the university are all taking courses______ a degree.（2010·01·山东烟台检测）

Before a problem can be solved, it must be obvious ________the problem itself is.(2011·湖南)