grist
/grɪst; ɡrɪst/ n
1 [U] (arch 古) grain to be ground 待磨的谷物.
2 (idm 习语) grist to the/sb's `mill useful or profitable, esp in addition to or as a contribution to sth larger 有益的或有利的东西（尤指对某事物的补充或补助）
I never refuse odd jobs to supplement my income it's all grist to the mill. 我为增加收入, 对於做零活总是来者不拒--多多益善.