if you define fewer levels of custom wbs codes than there are task levels, microsoft project " fills in " the undefined code levels with numbers ( or letters ), similar to the way it creates default outline numbers 如果您自定义的wbs代码级别少于任务的级别,microsoftproject会像创建默认的大纲编号那样用数字(或字母)“填充”未定义的代码级别。