Merge remote-tracking branch 'origin/dev_aliyun' into dev_aliyun

public/react/src/modules/courses/exercise/Studentshavecompletedthelist.js

@@ -1139,6 +1139,7 @@ class Studentshavecompletedthelist extends Component {
 					align: 'center',
 					className: "edu-txt-center font-14",
 					sorter: true,
+					defaultSortOrder: 'descend',
 					sortDirections: sortDirections,
 					render: (text, record) => (
 						<span>