Under the common counts the pleader need allege only that he is suing for unjust enrichment, for labor performed or for goods sold and delivered or services rendered but not paid for.

• 译：根据一般诉讼理由，原告只需宣称他所起诉主张的是（对方的）不当得利，已经付出的劳动，或已经出售并交付的货物，或已经提供服务但对方尚未支付价款。