When you're very, very afraid of something, that fear can affect (影响) you and how you live your life. When I was younger, I saw my cousin f____onto an ants' nest. The ants attacked (攻击) him, and he was c____in terrible bites(咬). After that I became very scared of ants. I wouldn't eat outside, and I didn't even like to play outside. I c____my bed for ants every night. But when I t____ thirteen, I decided I couldn't let my fear get to me. I had to learn to control my fear of ants.

    First I read a lot about different ants. I didn't focus on bites, but instead I read about how helpful ants are to the p____. Ants are really cool! They're hard-working, social, and organized. They help bring a____and nutrients(营养)to the earth. They help plants grow, clean up decaying(腐烂的)m____ and help control other insects.

    Next I began to w____ants from a safe distance. I started to look at a family of ants in real time on the Internet in order to learn how they live. Little by little, I felt more c____about ants. Finally I went outside one day and let an ant move onto my hand and t____it gently. It was okay! Now that I know about all the good things ants do, I'm not so afraid of them anymore.

若关于x的方程x2−2$\sqrt{k}$x−1＝0有两个不相等的实数根，则实数k的取值范围是（　　）

“不以规矩，难成方圆”告诉我们做任何事情都要有规矩。

如图所示，线框ABCD从有界的匀强磁场区域穿过，下列说法中正确的是（   ）