人红细胞无线粒体但能携带氧,红细胞所需能量的来源主要是利用[ ]
A.葡萄糖,进行有氧呼吸
B.葡萄糖,进行无氧呼吸
C.乳酸,进行有氧呼吸
D.乳酸,进行无氧呼吸
答案:B
A.室外冰冻的衣服变干
B.河面上结了一层厚厚的冰
C.正在跑步的人,口中呼出“白气”
D.冬天,窗玻璃上形成“冰花”
What he said is impossible, _______?
A.is it
B.isn't he
C.is he
D.isn't it