微分方程dy-2xydx=0在初始条件y(0)=1下的特解是（ ）．

单项选择题A．<br ><img src= {$uploaddir} c70ddba9-d130-4745-b9ff-ecd33e66c0c4.jpg >B．<br ><img src= {$uploaddir} ab649283-56f7-4ad3-80fc-35e2af6609b0.jpg >C．<br ><img src= {$uploaddir} 9652bbab-b3a3-497b-8182-cc83e1369f89.jpg >D．<br ><img src= {$uploaddir} d42d521b-72a9-4542-9cd9-de4b2f425d93.jpg >

单项选择题A．-7B．7C．-1D．1

单项选择题该处选项为（）。

A．This tour is the chance of lifetime．
B．It goes all over North America and South America．
C．It looks like you’re dreaming about something．
D．You’ll have to quit school and your job at the store．
E．My agent wants me to go on a tour with Art’s Jazz Band．
F．Have you told anyone about this yet
G．It would be a great opportunity!

单项选择题赵老师从因特网上找到了一份对自己有用的文字材料，他用复制、粘贴命令把它放到Word中，发现里面有大量的无用空格，他打算把这些空格全部去掉，下列方法中最适当的是（ ）．

单项选择题A: I’m terribly sorry that I broke your vase.B: ().

A. Thank you
B. It’s my pleasure
C. By the way
D. No, of course not
E. Never mind