完形填空（共20小题，每小题1.5分，满分30分）阅读下面短文，掌握其大意，然后从16－35各题所给的k^s5*uA.B.C.D四个选项中，选出最佳选项。 How did you do it, Dad? How have you managed not to take a drink for almost 20 years? It took me almost 20 years to have the 16 to even ask my father this very personal question. When Dad first 17 drinking, the whole family was on pins and needles every time he got into a 18 that, in the past, would have started him 19 again. For a few years we were 20 to bring it up for fear that the drinking would begin again.