滑阀产生液压卡紧的主要原因是由（）引起的径向不平衡力，减小该力的办法是在（）。
参考答案：滑阀副几何形状误差和阀孔中心线不重合；阀芯上开均压槽
下列各溶液中，c(Na+)最大的是
A．0.8 L 0.4 mol/L的NaOH溶液
B．0.2 L 0.15 mol/L的Na3PO4
C．1 L 0.3 mol/L的NaCl溶液
D．0.1 L 0.5 mol/L的NaCl溶液
按要求改写句子，每空一词。
1. Linda and Tom like French fries. (改为否定句)
Linda and Tom______ ______ French fries.
2. Does Tom like eggs for breakfast? (作出肯定回答)
______,______ ______
3. She doesn't have lunch at home. (改为肯定句)
She ______ lunch at home.
4. My teacher likes playing basketball. (改为一般疑问句)
______ your teacher ______ playing basketball?
5. We play volleyball. (变成由Let开头的祈使句)
______ ______ volleyb
