Which one of the following sentence is grammatically correct?
- Can we at least make this predictable?
- Can we make this at least predictable?
What is the grammar rule?
This is not a matter of grammar, but of semantics; that is, meaning.
The two sentences have slightly different meanings. Consider:
The above are not hard and fast, and also depend a lot on context and intonation. But the point is that shifting the 'at least' does change the meaning, however slightly.
They are both valid in different situations. It depends exactly what you are trying to say, and what "this" refers to.
They are both grammatical. They mean slightly different things.
This requests that if nothing else is achieved, the cat needs to be predictable.
This requests that if the cat can be nothing else, it should be predictable.