所谓每股利润的无差别点，是指不论采用何种筹资方式均使企业的每股盈利额不受影响，即使每

商店运来桃和苹果，桃和苹果的重量比是5：7，那么苹果重量占这两种水果总量的______．

已知递归函数f的定义如下：
int f(int n)

if(n＜=1) return 1; //递归结束情况
else return n*f(n-2); //递归

则函数调用语句f(5)的返回值是______。

科技创新愈来愈决定一个民族和国家的发展进程。[ ]

汽车沿着盘山公路可以驶上高耸入云的山峰，盘山公路修得弯弯曲曲，主要目的是为了__________，载重货车下山时，其重力势能_____（填“增大”“减小”或“不变”），为了减小车速，司机师傅不时踩刹车脚踏板，有一部分机械能转化为_____。

Melissa and Love Letter made use of the trust that exists between friends or colleagues. Imagine receiving an (26) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (27) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (28) .
As administrators seek to block dangerous email attachments through the recognition of well-known (29) , virus writers use other extensions to circumvent such protection. Executable (.exe) files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users.
Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the (30) access to your network.

A．attachment

B．packet

C．datagram

D．message,