吸气时,膈肌和胸廓的变化是( )
①膈肌收缩②膈肌舒张③胸廓缩小④胸廓扩大.
A:①③
B:①④
C:②③
D:②④
下列几何体中,主视图、左视图、俯视图完全相同的是( )
仿照所给的句子,续写两句话,使语意前后连贯,构成一组排比句。
与其咒骂黑暗,不如点亮一支蜡烛;
They were thirsty, so they went ______ something to drink.