如图所示，在探究并联电路的电流关系时，小明把阻值不等的两个灯泡接入电路中，用电流表测出通过A、B、C三点的电路分别为I_A、I_B、I_C．关于它们之间大小关系，正确的是（　　）

已知下列命题中：
（1）若$k\in R$，且$k\overrightarrow{b}=\overrightarrow{0}$，则k=0或$\overrightarrow{b}=\overrightarrow{0}$，
（2）若$\overrightarrow{a}·\overrightarrow{b}=0$，则$\overrightarrow{a}=\overrightarrow{0}$或$\overrightarrow{b}=\overrightarrow{0}$
（3）若不平行的两个非零向量$\overrightarrow{a}$,$\overrightarrow{b}$，满足$\left|\overrightarrow{a}\right|=\left|\overrightarrow{b}\right|$，则$(\overrightarrow{a}+\overrightarrow{b})·(\overrightarrow{a}-\overrightarrow{b})=0$
（4）若$\overrightarrow{a}$与$\overrightarrow{b}$平行，则$\overrightarrow{a}·\overrightarrow{b}=\left|\overrightarrow{a}\right|·\left|\overrightarrow{b}\right|$其中真命题的个数是（  ）

    To write a great news story, you have to make sure it is correct, relevant (相关的) and fresh.
    For a start, all the information in a story must be correct. Not only the spelling and grammar, but also the facts. Any mistakes that appear in a story can get a newspaper into big trouble. For example, if a newspaper said that Yang Liwei was the first man to go into space, it would be wrong. He wasn't the first. The newspaper would probably lose lots of readers because of that mistake
    A news story is not only correct , but also relevant to its readers. People are mostly interested in news that happens near to them. That is why you care more about what happens at your school than at American schools. It is also why newspapers in Beijing don't talk about much news in Shanghai or Hong Kong .
    Finally, news must always be fresh. When you pick up your evening newspaper, you want to read about news that happens that day. You don't want to read about news from last week!
    So, now you know what makes a good news story. Have a good look at our newspaper and see if it is full of good news .You can try writing a news story for our newspaper like a real reporter.