石棉肺患者的肺功能降低()
A.与X线胸片表现无关
B.往往比X线胸片表现出现得早
C.往往比X线胸片表现出现得晚
D.与X线胸片表现同步
E.与X线胸片表现相反
参考答案:B
一个圆锥形沙堆,底面半径是2米,高1.5米,这堆沙的体积是多少立方米?每立方米沙约重1.7吨,这堆沙一个重多少吨?(2分)(保留一位小数)
The student couldn’t _________what the teacher was trying to explain.
A.know
B.grasp
C.learn
D.get