题目

—I didn't hear you come in just now.—That's good. We tried __________ any noise, for you were sleeping. A . not make B . not to make C . to make D . making 答案：B已知x，y满足：x+y=π4且x，y≠kπ+π2（k∈Z），则（1+tanx）（1+tany）=（　　） A、-2B、2C、-1D、1