使用稀薄燃烧技术的汽油发动机，空然比可达（）以上，甚至高达23∶1。
A.19∶1
B.20∶1
C.21∶1
D.22∶1
参考答案：B
需要垫上石棉网才能加热的仪器是[ ]
A．
B．
C．
D．
Which accounting methods are preferable for income statements and balance sheets （）
A. LIFO for the balance sheet and FIFO for the income statement.
B. LIFO for both income statements and balance sheets.
C. LIFO for income statements and FIFO for the balance sheet.
