滞后环节的微分方程为()。
A.A
B.B
C.C
D.D
参考答案:C
—There isn't _____ good on TV. Let's go to the park.
—Good idea! [ ]
A. something
B. nothing
C. everything
D. anything
不符合大肠癌的描述是
A.多见于直肠、乙状结肠
B.多由腺瘤恶变而来
C.多为低分化腺癌
D.多分泌癌胚抗原(CE