紅茶がコーヒーより美味しいと思う


A native speaker corrected a learner's sentence from

> やっぱり紅茶はコーヒーより美味しいと思う

to

> やっぱり紅茶がコーヒーより美味しいと思う

I think 紅茶はコーヒーより美味しい sounds perfectly natural.

Using は with 思う also seems to be commonplace which I have always taken for
granted. Come to think of is though, it is interesting how 物理は難しいと思う is
natural with は although things preceding と思う could be bracketed as a content
clause (dependent clause). So I wonder if the reason for that correction could
be that dependent clauses call for が? But if that's the case why do a lot of
と思う sentences use は?




This が is an exhaustive-listing-ga, and whether it's desirable depends on the
previous context. You know when to say 私 **が** 英語ができる instead of 私 **は**
英語ができる, right? The と思う at the end of the sentence does not affect this
particle choice.

やっぱり紅茶がコーヒーより美味しい should be used when the speaker is faced with a choice
between the two options (tea vs coffee). For example, if this statement is
uttered after "Many people like coffee after lunch, but I don't like it", then
が sounds more natural (は is not incorrect, though).

