以下哪些属于上皮组织的特点()
A.C成分多、C间质少
B.无血管和淋巴管;有神经末梢分布
C.细胞数量少,种类多
D.无基膜
E.有极性,分游离面和基底面
参考答案:A, B, E
不用负数,请讲出下列各题的意义.
(1)某公司在2003年上半年营销情况是-50万元.
(2)向西走了-150米.
(3)运出-80吨大米.
Robert is said _______ abroad, but I don’t know what country he studied in.
A.to have studied
B.to study
C.to be studying
D.to have been studying