Split infinitives

Actually they are all perfectly correct. Sentences 1 and 4 are split infinitives.

Most grammar experts ignore the rule against split infinitives. It is a fake rule.

It comes from the fact that in Latin it is impossible to split an infinitive. There is no reason why English speaker should follow this rule. Often splitting an infinitive is quite useful for emphasis. The rule was popularized by a Grammar book called "Strunk and White". Most grammar experts think this book is wrong in several more areas.

American speakers split infinitives quite often. The phrase "to boldly go where no man has gone before" sounds much better than any of the alternatives.

However, if you have a teacher that says that you shouldn't split infinitives, then anytime you see an adverb between the word "to" and the "verb", move it.

But as soon as you leave this class, forget this bogus advice.

You just moved adverbs around.

Thank you very much for your quick answer.

However, according to the orders, there is only two correct answers. Which one do you think they are ?
That question is very tricky. According to your answer, and as my teacher is from England, I would say sentences 2 and 3. Am I right ?

It is pretty obvious. This test is designed to get you to reject split infinitives. So find the ones that don't contain split infinitives (which would be 2 and 3).

Here is a source from England (ironically blaming this silly rule on editors in the USA).

http://www.lel.ed.ac.uk/grammar/splitinf.html

This article gives examples of well known and respected authors using split infinitives in their masterpieces.

In my opinion, this rule is stupid in any English speaking country.

If you are learning English as a second language, shouldn't they be focusing on how the language is commonly used (rather than on weird archaic rules)?

If you go on the street of England or the USA you will hear people using split infinitives. If you move adverbs around to avoid split infinitives, it will make you sound awkward (since that isn't how native speakers talk).

The more I think about this, the more it bothers me.