Let's say you've been waiting to speak with someone in their office. You're outside in a waiting room. They open the door. Any of these phrases could come out of their mouth:
Sorry to keep you waiting.
Sorry to have kept you waiting.
Sorry for keeping you waiting.
Sorry for having kept you waiting.
The only nuanced difference, and it is a very slight one indeed, is that with the perfect your wait is presented as something which is now at an end.
Even though the non-perfect versions could be spoken when the person is ready to see you, so that you're no longer waiting, they could also be spoken when the person is asking you to wait a little longer.
Sorry to keep you waiting. It will be just another 5 minutes. Thanks for being patient.
If the person used the perfect in that case, you might momentarily think that your wait was over, making the added wait a tad more irksome if only because you thought the wait was over:
Sorry to have kept you waiting. You may infer your wait is over and begin to stand up. But it will be just another 5 minutes.
First, let's start with a declarative main clause:
It's supposed to look like this.
We'll turn it into a question by replacing this with what:
It's supposed to look like what?
But this sort of question is only allowed under special circumstances – for example, if you couldn't hear what someone said, or if you wanted to express incredulity at what they said.
Let's turn it into a normal question instead (an interrogative clause):
What is it supposed to look like ＿＿＿?
We did two things here:
- We moved what to the front of the sentence, leaving behind a gap, which I've marked using an underline. Normally the gap would not be written down.
- We inverted the subject it with the auxiliary is.
We had to do step #2 because this was a main clause; main clause interrogatives are marked by subject–auxiliary inversion, unless the wh-phrase is part of the subject.
In your example, we have the same thing, except it's a subordinate clause:
Is that [ what it's supposed to look like ＿＿＿ ] ?
Subordinate interrogatives are not marked by subject–auxiliary inversion, so the only thing we need to do here is move what to the front. The subject and auxiliary remain in their original order: it's, not is it.
Your version is the same thing, but it omits the subject it:
*Is that [ what ∅'s supposed to look like ＿＿＿ ] ?
Here, the ∅ symbol indicates that something has been left out. However, there is nothing that would allow you to omit the subject here, so your example is ungrammatical.
In this answer, the * symbol indicates that a sentence is ungrammatical.
Best Answer
It would be okay to leave just one expression:
You might add some adjunct to it to stress your need for a continuous contact:
.. sentences 1 and 2 would mean that the period of "continuous contact" will start at the moment of arrival to the college.
You can say:
.. this would mean that there is an ongoing contact between the parents and the son, and that the parents want to remain in the same kind of contact with their son after he arrives at the college.
You indeed can combine "keep on" + "keep in touch", but you would need to turn the second expression into "keeping in touch":
.. the meaning would be similar to sentence 3.
But people tend to avoid having two similar expressions close to each other, because such constructions look strange, despite being grammatically correct.
You can use "keep on keeping in touch" as a kind of wordplay to amuse yourself or your listeners, to make someone stop and notice this strange combination, but not too often. (0:
There is an expression that uses this effect: "keep on keeping on" - meaning "keep trying, keep doing what you are doing". It's used in poetry and songs: