写出两个无理数，使它们的和为有理数______．
∵两个无理数的和为有理数，
则这两个无理数互为相反数，
如：3，-3等．
I _____ an interesting programme _____ animals last night. [ ]
A. watch; of
B. watch; about
C. watched, of
D. watched; about
计算题：东风4型内燃机车启动瞬时的黏着系数是多少？
