我正在将Bootstrap-scss 3.7.7升级到Bootstrap 4.0.0，卸载Bootstrap-scss 3.7.7然后尝试安装Bootstrap-scss 4.0.0后出现此错误：
at options.error (C:\wamp64\www\QuizApp\node_modules\node-sass\lib\index.js:291:26)
status: 1,
file: 'C:/wamp64/www/QuizApp/resources/assets/sass/app.scss',
line: 9,
column: 1,
message: 'resources\\assets\\sass\\app.scss\nError: File to import not found or unreadable: ~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss.\n on line 9 of resources/assets/sass/app.scss\n>> @import "~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss"; \n
^\n',
formatted: 'Error: File to import not found or unreadable: ~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss.\n on line 9 of
resources/assets/sass/app.scss\n>> @import "~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss"; \n ^\n',
messageFormatted: '\u001b[4mresources\\assets\\sass\\app.scss\u001b[24m\nError: File to import not found or unreadable: ~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss.\n on line 9 of resources/assets/sass/app.scss\n>> @import "~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss"; \n ^\n',
messageOriginal: 'File to import not found or unreadable: ~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss.',
relativePath: 'resources\\assets\\sass\\app.scss',
name: 'Error',
stack: 'Error: resources\\assets\\sass\\app.scss\nError: File to import not found or unreadable: ~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss.\n on line 9 of resources/assets/sass/app.scss\n>> @import "~bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss";
\n ^\n\n at options.error (C:\\wamp64\\www\\QuizApp\\node_modules\\node-sass\\lib\\index.js:291:26)',
showStack: false,
showProperties: true,
plugin: 'gulp-sass' }
App.scss line 9
@import "node_modules/bootstrap-sass/assets/stylesheets/bootstrap/bootstrap.scss";