计算（结果保留小数点后四位）

（1）sin23°5′+cos66°45′

（2）sin²7.8°﹣tan15°8′．

已知二次函数y=ax²+bx+c（a≠0）的图象如上图所示，有下列5个结论：①abc＞0；②b＜a+c；③4a+2b+c＞0；④a+b＞m（am+b）（m≠1）
其中正确的结论有（　　）

下图是油菜种子在发育和萌发过程中糖类和脂肪的变化曲线。下列分析正确的是

如图，温度计的示数是____ 　．我国第一个南极科学考察基地﹣﹣中国南极长城站的平均气温为﹣25℃，最低气温可达﹣88.3℃，依据图表提供的数据，在南极长城站测气温时应选用____ 温度计．

    “How can I learn English well?” “This is a 1 many students may ask. In my opinion, the most effective(有效的) 2 is to learn lessons by heart. If you can recite the text and write it out, you will learn it pretty well. And if you can tell 3 your own words about 4 the lesson says, you are a very successful learner indeed. Your English will be quite perfect.

    This is a difficult task. However, if you try to learn by heart only part of each lesson, you'll find it not so hard 5 you might have thought.

    Learn this way, and you will 6 fast progress. Of course, writing is also necessary. It helps you a lot on your way to 7 in English studies.

    It's equally(同样地) important to feel the language. You should laugh at English jokes and be 8 at bad news. When using English, try to 9 your mother tongue(母语). 10 helping you, your own language gets in your way. So, never try to learn English through putting every word into Chinese.