After getting annoyed that the default 2017 theme was showing the full post content on every index page, I extended this support answer into this plugin that can filter calls to "the_content" and return the post excerpt instead.
安装:
Upload the plugin files to the /wp-content/plugins/always-show-excerpts/ directory, or install the plugin through the WordPress plugins screen directly.
Activate the plugin through the 'Plugins' screen in WordPress
Go to the Settings -> Reading page to configure the plugin, picking which types of archives should be affected.