I agree. Where possible you should focus on learning phrases or short sentences, preferably easy, common ones that can be understood and regardless of the context and/or. The phrases should be mastered to the point of understanding them at a fast normal speed.
Examples might be “Wait a minute”, “What do you mean?”, “What did he say?”, “What do you think?” “When can you do it?”, “How is it?”. “I don’t agree”. “I agree”. “That’s right”. “What are you talking about?”. “Are you nuts?” etc.
Drilling rapidly “What is he talking about?”, “What is she is talking about?”, “What are they talking about?”, “What are you talking about?” could also be good, as long as it achieves fast normal speech and doesn’t dwell too much on grammar in the abstract.
I’m a big fan of language drilling but it seems to be out of fashion, perhaps because it seems militaristic. Also, like drilling on a parade ground, it is a lot more fun than it looks, especially after you’ve done it quite a bit. It grows on you. It can feel like a game when it’s really fast, and even a meditation.
It is a type of rote learning I suppose. Rote learning also has an undeserved bad name.
The type of drill I am talking about is when you listen and repeat, and then substitute a word and say the new sentence at a fast normal speed, e. g.
T (teacher): “Eating at home.”…“School”
S (student(s)): “Eating at school.”
S: Sleeping at school
T: in church
S: Sleeping in church
S: Eating in church
S: Running in church
Instead of a teacher you can use an audio file.