No one knows ______ the task will last. What a pity!A．how long

Jackson has got to be crazy ________Chinese culture since he visited China last time.

The shirt looks very nice. I guess it is _______ 100 yuan.

The mother is very glad; her baby isbeginning ______.

When I opened the door, I found my father ________ in his chair, completely _______ in a magazine.