The computer system ______ suddenly while he was searching for information on the Internet. [ ]

The reason ___ he can’t come is ______ hehas to work late.

The electronic red-packet has been so ______ that AliPay and Tencent Wechat compete against each other openly and secretly since the beginning of this year.

She was such a proud person that she would die ______ she would admit she was wrong.

Only after the plane had taken off _________ that he missed his parents so much.