crash:if a computer crashes or you crash a computer, it stops working suddenly 崩溃
Files can be lost if the system suddenly crashes.
要是计算机系统突然崩溃,文件就可能丢失.
attachment:a document that you send to somebody using e-mail (用电子邮件发送的)附件
virus:instructions that are hidden within a computer program and are designed to cause faults or destroy data (计算机程序中的)病毒