—Tina, I have cleaned most of the windows.—That's very kind ___ you. It's difficult me to do it all by myself.
A:of; for
B:for; of
C:for; for
D:of; of
贝加尔湖是世界上最深和蓄水量最大的淡水湖。俄国作家契诃夫曾描写道:“湖水清澈透明,透过水面就像透过空气一样,一切都历历在目,温柔碧绿的水色令人赏心悦目……”。下面左图为贝加尔湖位置示意图,右图为某年5月贝加尔湖遥感影像。读图,贝加尔湖周围地区冬季平均气温约为-38℃,而冰层以下的水温与夏季接近,其原因是( )
yǔn xǔ
tān wán
rèn píng
róu ruò
____
列各项中,说明生物需要营养的是( )