下列长度的各种线段,可以组成三角形的是()
A. 1 ,2,3
B. 1 ,5,5
C. 3 , 3,6
D. 3 ,5,1
It is essential that you__________any document carefully before signing it.
A. read
B. reading
C. can read
D. have read
一般情况下,不引起犬支气管炎的病毒是()
A. 犬细小病毒
B. 犬瘟热病毒
C. 犬流感病毒
D. 犬腺病毒II型
E. 犬副流感病毒
下列计算结果正确的是()
A. (﹣2x 2)^3=﹣6x^6
B. x^2x^3 =x^6
C. 6x^4÷3x3 =2x
D. x^2 +x^3 =2x^5