有用do good to;of service;serve her turn;useful详细»
有用be of avail;be of help;be of service;be of use;did good;do good;do good to;serve her turn;serve his turn;serve my turn;serve our turn;serve their turn;serve your turn;useful详细»
有用be of avail;be of service;did good;do good;of use;usefulness;utility详细»
有用am of avail;am of service;are of avail;are of service;do good;is of avail;is of service;was of avail;was of service;were of avail;were of service详细»
有用am of avail;am of service;are of avail;are of service;do good;usefulness;was of avail;was of service;were of avail;were of service详细»