bare-infinitivegrammaticalityverbs
I was speaking to an English learner and said, “All you have to do is read a lot.” And they thought that sentence wasn’t grammatically correct because I dropped the word to between is and read.
They thought it should be “All you have to do is to read a lot.” That sounds weird to me.
How do I explain to them the reason you drop the to? Or am I incorrect and it really should have a to?
It seems to me that you want to use "it" as a Dummy Pronoun (like I have in this sentence). However, you are actually using "it" to refer to "the reason".
Furthermore, I would not use "looks" to describe the intangible noun "reason". A suitable replacement might be "seems" or "feels".
A possible reconstruction (with the substitution) could be:
It seems weird to me that they chose this way.
or
It seems weird to me that they chose this way for the reason that they did.
It’s not grammatically wrong, just unconventional. Most people would use the connecting word that:
It is the way that we write.
You could also see:
It is the way in which we write.
You can, for example, compare the relative frequency of these phrases in print using Google Ngram Viewer. The chart below compares “is the way how”, “is the way that”, and “is the way in which”. It appears from the chart that “is the way how” is virtually never seen in print. The other two are seen regularly, but for the past 200 years “is the way in which” has been more popular.
Click on the chart to interact with it. You can, for example, separate the results for British and American English.
Best Answer
The reality of the language is such that both forms are used, on both sides of the Atlantic, but the bare-infinitive form is clearly preferred, as the stats from the Corpus of Contemporary American English (COCA) and the British National Corpus (BNC) illustrate:
The preference does not change if all is replaced with what, if an adverb is introduced before the infinitive, or if a different pronoun is used instead of you. However, what also does not change is that the variant with to at least exists. (A peculiar exception seem to be she and it; negation is another interesting case, but the sample size is sadly too small for those). Sometimes the ratio is a mere 1:60, but other times it's not anywhere as cut and dry. Here are all the stats I have compiled so far:
So if you want to be on the safe side, bare infinitive certainly is the way to go. It also happens to be the more logical choice, as demonstrated by FumbleFingers in his answer. But we can't label the other option ungrammatical, and its existence can be explained logically as well, as metanalysis.