Bootstrap‘s JavaScript requires jQuery

1、遇到的第一个问题：modal.js:6 Uncaught Error: Bootstrap’s JavaScript requires jQuery
at modal.js:6
2、遇到的第二个问题：countdown.js:6 Uncaught ReferenceError: jQuery is not defined
at countdown.js:6
at countdown.js:8

3、遇到的第三个问题：OneYearHandle.html:202 Uncaught ReferenceError: $ is not defined
at OneYearHandle.html:2021

待解决