熔池晶核长大时所增加的表面能形成晶核时所增加的表面能要小，所以，晶粒长大比形核所需的过冷度（）.
A、要小
B、要大
C、相等
参考答案：A
对口腔颌面部鳞癌化疗药物可选用（）。
A.争光霉素+长春新碱+喜树碱
B.环磷酰胺+长春新碱+阿霉素
C.争光霉素+长春新碱+氨甲蝶呤
D.氟脲嘧啶+环磷酰胺+白力霉素
E.争光霉素+白力霉素+长春新碱
同义句转换
1. He concentrated his energies on study.
He _his energies _ study.
2. I must concentrate on my new task.
I must be _ _ my new task.
3. He fixed his eyes on his book and didn't notice we came in.
He his attention his book and didn't notice we came in.
