粒子系统是一个比较复杂和庞大的组件。例如在一个场景中频繁出现的爆炸粒子特效,我们可以怎样对它进行一定的优化处理?
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在下列临床常用的抗菌药中,属于主要作用于革兰氏阳性菌的抗生素为:
A. 红霉素
B. 庆大霉素
C. 磺胺嘧啶
D. 强力霉素
E. 环丙沙星
抗生素的作用机理为:
A. 破坏已形成的粘肽结构
B. 阻止十肽二糖聚合物的交叉联结
C. 阻止D-丙氨酰-D-丙氨酸的形成
D. 阻止β-内酰胺环的形成
E. 阻止粘肽中多糖链的形成
下列药物作用机制错误的是
A. 青霉素G-抑制转肽酶
B. 利福平-抑制依赖DNA的RNA多聚酶
C. 异烟肼-抑制分支菌酸合成酶
D. 5-FU(5-氟脲嘧啶)-抑制DNA多聚酶
Mary: Hi, John! How are you 1) _______________?John: Not bad. How about you, Mary?Mary: Fine, thank you. John, this is my friend Rose. She’s studying 2) _________ here.John: How do you do, Rose?Rose: How do you do, John? It’s a 3) ________________ to meet you.John: Pleased to meet you, too. Mary has told me a lot about you. I’ve been looking forward to 4) _____________you.Rose: Same here.Mary: John, there’s a 5) ______________ on campus this evening. Would you like to go with us?John: I’d love to, but I’ve already made 6) _______________.Mary: That’s too bad!