When I read Catechism, the term “grace” is quite confusing. There are at least four types of grace I read: sanctifying grace, habitual grace, actual grace, and special grace. So, recently, I tried to solve my confusion by going through these differences. By reading the Catechism again and again (the related part only), and also some other resources, so, I simplify them,

Sanctifying (or deifying) grace = 圣化恩宠, permanent state of grace. Habitual grace = 常居的恩宠（宠爱）, is also sanctifying grace. Actual grace = 现时的恩宠（宠佑）, transient help to act (intervention of God), different from habitual grace. Also called “gratuitous grace” in Summa Theologica. Special grace = 特别的恩宠（神恩）, also charism, oriented to sanctifying grace. Considered actual grace.