The first three phrases mean the same thing - to enter your personal credentials (big word for username and password) so you can access the content of a website that is only available to its members or subscribers. 'Register' means to create an account for a website by supplying a unique username and password. After you register and have an account, you can then log in to the website. I answered you assuming that this is in reference to the internet.

Another vote for Criminal Minds!

I might say the following.... "In creating our line of financial products, we are focused on the rate of implementation - liquidity, profitability and safety of our capital and the capital of our clients. With a team of first-class professionals, we follow a high standard of quality and competence in service and money management." I'm not sure if the phrase "In cooperation with international partners" fits too well with how and why you are following a high standard of quality. Of course, I don't know the context of the situation so I'm making very big assumptions when I advise you on your text. I'm not sure the phrase "rate of implementation" is the correct one but again, I don't know anything about the situation.

It can be used with or without the article. I think you will see it far more often without it. An example of usage with the article is, "what is the danger in mixing those two chemicals?"

"Other" is usually used to differentiate between two items as in, "I don't want this one. I want the other one." "Another" is often used to indicate "one more" as in, "I'll have another cookie, please!" But there are probably more uses of these words than what I have described.

It's incorrect English but sometimes phrases like this are used over and over to the point where they become a recognized phrase in our language. Most likely, we've all heard it and know what is being implied. It's better to say, "all you can say is sorry?" It reminds me of the phrase, "I could care less!" where the correct form is actually, "I couldn't care less". But saying it incorrectly is quite common. My guess on why we say "I could care less!" is that it flows better and is easier to say.

Your usage is perfect and there is no impropriety at all in what you said. Well done!

Mariana, it would be extremely rare for you to conjugate a sentence with 'somebody' as the subject and 'explains' as the verb. If you did find such a sentence, it would more likely be in the past tense as in, "somebody explained to him how to understand women". Of course, that is fiction but it is still a good example. :) I think the phrase you are asking about is actually in the command form as in, "somebody, please explain to me how to use this software!" In this case, "explain" has no "s" on the end. This would be a very common phrase using "somebody" and "explain". I hope this helps.