他的电脑毫无预警地崩溃了。

His computer ___crashed without any warning.

我希望系统不会在重要的演示期间崩溃。

I hope the system won't ___crash during the important presentation.

在最近一次更新后，该软件开始频繁崩溃。

After the latest update, the software started to ___crash frequently.