焊接熔池的二次结晶的组织及性能与（）有关。
A.冷却方式
B.冷却速度
C.冷却介质
参考答案：B
羟甲戊二酰辅酶A还原酶抑制剂可以
A．抑制体内cAMP的降解B．抑制血管紧张素I向血管紧张素Ⅱ的转化C．阻止内源性胆固醇的合成D．降低血中三酰甘油的含量E．促进胆固醇的排泄
Ron can type five forms of a test in 4 hours. Joan can type the same five forms in 6 hours. If they work together, how many hours would it take them to type ten forms of a test
