题干
After we sat down, Father the menu and ordered my favorite dish for me.
A：looked after
B：looked like
C：looked through
D：looked for
答案(点此获取答案解析）
C
＝2a＋pb，
＝a＋b，
＝a－2b.若A、B、D三点共线，则p的值为( )