实际操作时，泵实际所能输送的液体量还与（）和（）有关
参考答案：管路阻力；所需压力
Not until the early years of the 19th century ________ what heat was. [ ]
A. man did know
B. did man knew
C. didn't man know
D. did man know
哪个面神经支司管下唇的运动和口角平衡（）
A.面神经
B.颧支
C.颊支
D.下颌缘支
E.颈支
