In my never so humble opinion, prepositions are perhaps the most confusing aspect of English. I happened to chat with two non-native speakers about that today and they both agreed. Is the Internet catching on or catching up? What does "make up" mean? (Answer: about 20 different things.) Etc. It's crazy! My favorite example is the classic story of a young child whose parent comes upstairs to read a bed-time book. But the child doesn't like book the parent brings upstairs (children are picky!), so he says "What did you bring the book that I don't want to be read to out of up for?" Yes, that sentence is perfectly good English (albeit a bit confusing), and it ends with 5 prepositions! As I say, it's crazy...

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