Does this sentence sound right?

Sealions can dive to a depth that humans cannot reach, so they could carry cameras on their backs to record the natural behavior of whales without disturbing the whales' natural living patterns.


Pretty good, Ahava.

Thank you Mister Micawber. I find you change the first "could" into "can", while leave the second one as it is. Is it because it is an unchangeable face that they dive deep, but they might "carry cameras"? So for a definite fact, use "can", for something unusual we use "could", is that so? Thank you again!

Yes, that was precisely my point, Ahava. Here, 'can' for ability and 'could' for possibility. (I don't think unusualness enters into consideration, though.)

I see. Thank you.

Hi Mister Micawber, I've another question to bother you. If I want to say, it'll take five years to train each group of sealions to do certain task, what should I define this "five years", can I say the time circle is five years? or maybe there's a better one for this meaning.

and if it says this phase of training can take a year. Can I interpret it as "the training will take at least

'The training will take at least a/one/five year(s).' -- these are perfectly adequate for your purpose, I think.

That they 'five-year training cycle' is a nice phrase, if you feel it is necessary to stress the coordinated, periodic production of groups of trained pinnipeds. Each group, however, does not undergo the cycle, but just the repeated 'training program' within the cycle.

Thank you Mister Micawber, thank you very much for the detailed explaination. I just want to make sure one point,

the training can take five years
the training takes at least five years

Does the "can" here in the first sentence carries the meaning of "at least" shown in the second sentence? Is "can" here just a possibility or a necessity?

I appreciate your pati

'the training can take five years' = five years is the maximum, but the maximum is often required. 'Can' is possibility here.

'the training takes at least five years' = five years is the minimum, and it may be longer.


Don't fret about prolixity-- the moderators have you outdone in that department.

Thank you
Now I'm absolutely clear about that sentence.

I don't quite understand "the moderators have you outdone in t

Yes. We are more prolix than the students, I fear. Never let that worry keep you from posting as much as you want to, Ahava-- that's what English Forum is about: using the English language.