René Descartes' saying "Cogito ergo sum" has been widely spread all over the world. In English it is commonly known as "I think therefore I am", but it is also known to us that "therefore" is not a conjunction, and thus the proper sentence should be "I think. Therefore I am" , "I think; therefore I am" or even "I think, and therefore I am".
Regardless of that, I wonder if "I think therefore I am" is not grammatically correct, then how can it be accepted by the whole English world?
Hence how to figure it out?
Recently I plan to brush up my German and read a book on German usage, which says that the sentence "Du gefällst mir nicht" refers to someone’s health and indicates that the speaker is concerned that you are looking ill...But literally it simply means "I don't like you", so I take this interpretation with a grain of salt, because it must produce ambiguities.
Besides, it also says that the sentence "deine heiße Stirne gefällt mir nicht" is not a comment on your (lack of) beauty but implies that you may be running a temperature, I thought it may be right to have an interpretation like this, but still not very sure.
Could some native speakers shed light on those two sentences? I've never heard of them before.
Thanks in advance.
