Tony,don't forget your homework to me after school.
A:bringing
B:to bring
C:taking
D:to take
飞机向地面俯冲,飞行员看到大地扑面而来,这时飞行员选的参照物是( )
利用下图所示装置探究酵母菌的无氧呼吸,正确的操作方法是 ( )