倾角为θ的斜面上有质量为m的木块，它们之间的动摩擦因数为μ．现用水平力F推动木块，如图所示，使木块恰好沿斜面向上做匀速运动．若斜面始终保持静止，求水平推力F的大小．

Thank you for inviting me to this evening party.____ 

    Mrs. Green works very long hours every day. She usually gets up(起床 ) at 5:40. She brushes her teeth(刷牙) and goes to her workplace (工作地点). Then she runs with some kids. After that she takes a shower(淋浴). she eats her breakfast at 7:00. Her work starts(开始) at 8:10. she is good at(擅长 ) history and many boys and girls learn history from her. All the kids（孩子） like her very much. She often talks or plays games with the kids. She  usually goes to bed(睡觉) after 22:00. she is often very tired(劳累) but she likes her job and loves the kids. She doesn't work on weekends. Mrs. Green likes reading at home on weekends(周末). Sometimes some kids' parents come to her home to talk about their kids. When Monday comes, Mrs. Green gets busy again.

2015年7月；***提出，推进国有企业改革，要有利于国有蓝本保值增值，有利于提高国有经济竞争力，有利于放大国有资本功能。下列对此观点理解正确的是（  ）

①实现国有资本保值增值有利于促进国有企业可持续发展

②放大国有资本功能有利于各种所有制经济相互竞争和发展

③放大国有资本功能能有效增强国有经济控制力和影响力

④提高国有经济竞争力需要巩固公有制的主体地位