keep try放在句头,try要加ing还是to

keep 加ing keep + doing sth. 表示保持 一直做某事

keep的用法就是 keep doing 所以无论在哪里都是加上ing

keep trying
是个固定结构keep doing sth.

keep doing sth.是固定用法.
keep trying to...

Keep trying to practice.
try to是努力做什么
try doing 尝试