PHP 错误：“zip 扩展名和解压缩命令都丢失，正在跳过。

当我运行一个我得到这个错误消息：composer update

Loading composer repositories with package information
Updating dependencies (including require-dev)
    Failed to download psr/log from dist: The zip extension and unzip command are both missing, skipping.
The php.ini used by your command-line PHP is: /etc/php/7.0/cli/php.ini
    Now trying to download from source

我需要执行哪些操作才能启用 zip 和解压缩命令，以便 Composer 可以下载依赖项？