我刚刚运行sudo npm update -g，输出包含有关未满足依赖项的警告消息。这是一个摘录：
npm WARN deprecated grunt-bower-install@1.6.0: use grunt-wiredep instead
strip-ansi@0.1.1 /opt/local/lib/node_modules/bower/node_modules/chalk/node_modules/strip-ansi
intersect@0.0.3 /opt/local/lib/node_modules/bower/node_modules/bower-json/node_modules/intersect
object-assign@0.1.2 /opt/local/lib/node_modules/yo/node_modules/insight/node_modules/object-assign
array-filter@0.0.1 /opt/local/lib/node_modules/bower/node_modules/shell-quote/node_modules/array-filter
graceful-fs@2.0.3 /opt/local/lib/node_modules/npm/node_modules/cmd-shim/node_modules/graceful-fs
ansicolors@0.2.1 /opt/local/lib/node_modules/bower/node_modules/cardinal/node_modules/ansicolors
strip-ansi@0.1.1 /opt/local/lib/node_modules/generator-angular/node_modules/chalk/node_modules/strip-ansi
npm WARN unmet dependency /opt/local/lib/node_modules/bower/node_modules/insight/node_modules/inquirer requires async@'~0.2.8' but will load
npm WARN unmet dependency undefined,
npm WARN unmet dependency which is version undefined
object-assign@0.1.2 /opt/local/lib/node_modules/bower/node_modules/insight/node_modules/object-assign
npm WARN unmet dependency /opt/local/lib/node_modules/gulp/node_modules/vinyl-fs/node_modules/glob-stream/node_modules/glob requires minimatch@'0.3' but will load
npm WARN unmet dependency /opt/local/lib/node_modules/gulp/node_modules/vinyl-fs/node_modules/glob-stream/node_modules/minimatch,
npm WARN unmet dependency which is version 0.2.14
unique-stream@0.0.5 /opt/local/lib/node_modules/gulp/node_modules/vinyl-fs/node_modules/glob-stream/node_modules/unique-stream
rimraf@2.2.8 /opt/local/lib/node_modules/npm/node_modules/fstream/node_modules/rimraf
npm WARN unmet dependency /opt/local/lib/node_modules/cabin/node_modules/inquirer requires lodash@'~1.2.1' but will load
npm WARN unmet dependency /opt/local/lib/node_modules/cabin/node_modules/lodash,
npm WARN unmet dependency which is version 2.2.1
造成这种情况的原因是什么？它可以修复吗？