上冻前将引杆、蔓一起割掉,及时冬耕地后用干土埋根堆包()。
A、保墒
B、保鲜
C、防冻害
D、防虫
参考答案:C
He felt ____by his lack of money when his friend asked him for help.[ ]
A. embarrassed
B. embodied
C. embraced
D. worried
对病毒生物学性状的描述,不正确的是()
A.测量大小的单位为纳米(nm)
B.含有DNA和RNA两种核酸
C.以复制方式增殖
D.必须寄生于活细胞内
E.属于非细胞型微生物