无砟道床,板式轨道混凝土底座厚度应大于等于()cm。
A.10
B.15
C.20
D.25
参考答案:B
I just choose a simpler lifestyle, ________ where I can ride my bike all over and do not
have to make a great living to survive. [ ]
A. it
B. that
C. the one
D. one
实验室制取CO2有以下步骤操作: (1)向试管里装入大理石、(2)检查装置气密性、(3)收集气体、(4)向长颈漏斗中注入酸液,操作顺序排列正确的是
A.(1)(2)(3)(4)
B.(2)(1)(4)(3)
C.(2)(4)(1)(3)
D.(1)(4)(2)(3)