A:that; where
B:which; that
C:where; that
D:which; where
如图,在边长为1个单位长度的小正方形组成的网格中.
More than two weeks _______ since the foreign friends came here.
当血液经过肺泡周围毛细血管时,血液中的氧含量发生变化,正确表示该变化的曲线( )