Related words and phrases:
A boyfriend and girlfriend are talking ...
Boyfriend: What's wrong?
Boyfriend: Something is wrong. I can always sense when you are upset with me.
Girlfriend: OK, so if you can tell that I am upset with you, can you tell what I am upset about?
Boyfriend: No. I can't figure that out.
Two colleagues are talking ...
Colleague 1: I'm having trouble with this year end report. Could you take a look at if for me, please.
Colleague 2: Sure. OK. It looks like there is a problem with the first quarter numbers.
Colleague 1: How can you tell?
Colleague 2: After having done ten or so of these reports, you get an understanding of what the numbers should look like.
Colleague 1: Thanks.
There is no gerund form for can tell.
1) ... you describe really have nothing to do with science, as far as I can tell.
2) I also like buying used because I can tell the quality of the item.
3) You can tell how important a team will be to the story by how many players get names ...
4) And yet, I can tell that this comment is stupid.
5) The undefined level is unbeatable, as far as I can tell.
6) They are looks of sympathy. I can tell in others eyes that they are glad they are my shoes and not theirs.
7) I hardly can tell you lost weight.
8) I can tell that is a myth that may never die.
9) As far as I can tell, Egyptian security did little or nothing after the last round of fire on Israel ...
10) The pain echoes harshly, then fades into a dull ache. I can tell I'll have a bruise tomorrow.
11) Hwang never heard back, and from what I can tell, Johnson almost never communicates with his fans, let alone journalists.
12) I wouldn't miss this one for the world buddy. I can tell how hard it is to produce a movie, or even a small documentary.
13) ... but he's blushing when he says it, and you can tell by his voice that he's lying.
14) The only way I can tell that I did anything was by how dizzy I was getting and by how strange ...
15) I think you're video (and from what I can tell your opinion in general) has been the most unbiased and neutral opinions about ...
16) The townspeople first reach the conclusion that they can tell if she's a witch by throwing her into the pond, ...
17) Of course, this is an easy example so you can tell by just looking at it.
18) ... the Buddha is described on at least one famous quotes site, so we can tell where these authors source their quotes.
19) ... managed pretty well now because I have been doing this for so long and can tell when things are going to flare.
20) I can tell it's an ad by looking on other browsers without that extension.