我的电脑被病毒感染了。

My computer was ___infected by a virus.

确保你的杀毒软件处于活动状态，以防系统被感染。

Ensure your antivirus software is active to prevent your system from being ___infected.

打开来自未知发件人的电子邮件附件很容易使你的电脑感染病毒。

Opening email attachments from unknown senders can easily ___infect your computer.