練習を意味するpracticeは不可算名詞なのでaはつかない。 practiceの後につけられる前置詞は幾つかある。いずれもネットからの引用です。 I was already putting in quite a lot of practice on the piano and ... 洋書からの引用。 We worked on this together, and the exercise not only gave him practice in writing, but ... The US military sends its doctors to Chicago to give them practice for gunshot wounds. Once your little ones gain practice in riding a tricycle, they develop a sense of balance and ... It allowed us to gain some practice with interviews before we go into more jobs and getting a solid career. 以下はto不定詞の例 ... give them practice to use imperatives in day-to-day conversation.