When parents help their babies or kids pee, do they say or make a sound"psss" in English? Is the "psss" common in English?

Past vs Past Perfact? In a report that describes the results of our engineering activities, I am confused whethr it is better to use just the past tense or past perfact tense. Which is better in a final report? 1) We calculated it, or 2) We have calculated it. 1) It was estimated based on ~~ 2) It has been estimated based on~~ I am thinking for both cases above, 2) have/has PP is better, but I am not sure, so let me have you guy's advices. Also, what about the following case which is NOT describing what have been done, but just describing the basis of the report which can seem like a present tense in a way, for example: 1) The weight of the equipment is excluded from the report 2) The weight of the equipment has been excluded from the report 3) The weight of the equipment was excluded from the report Which one is better,right, or wrong in a report? Thank you in advance!

What's the best way to respond to someone's introduction in email? In a business email, someone got an information about me through his colleague so he sent an email to me like "XXX gave me your name and info. I am ~~~. I'm writing to~~~". So, in response to this email, what's the best way to start my email with? Can I say: "Nice to meet you" or "Pleased to meet you? - Can I say this even for this virtual meeting through email only, not in person? "Pleased to get your email"? - I am an information provider so no reason to be "pleased" to get a question actually. Or is there any verb I can use to lightly greet our virtual meeting online?

Hi. How do I "read" the below hour, minutes, and time "at the same time"? 11: 32: 42 (Hour: Minute: Second) Can I just say "Eleven, thirty two, forty two"? Or "Eleven, thirty two, forty two seconds"? It is not the period of time but a specific time. Thank you in advance for your help!

London time. Is London time now GMT+1 reflecting summer time zone now?

I want to say "the cake is so pretty that it feels like I shouldn't eat it to keep it pretty". But I will eat it anyway, and I just say it to emphasize that the cake is that much pretty. 1. In this case, can I say "This cake is too pretty to eat"? 2. Using this "too~to~" pattern is only for the case that I really don't eat the cake to keep it pretty? 3. Or, using this "too~to~" pattern has some negative nuances, like the cake is pretty in a negative way?? The reason of my question is that I want to express how I feel in a simple way, not in a lenthy and complex way, and I thought it may be a good way to use this "too~to~" pattern to make it simple. But I'm afraid in regard to the above aspects. Thank you for your help in advance!

Come to know Vs Know Hi! If I added "come to" in front of "know", is it showing that I become aware of something? What does exactly the additional "come to" function? Also can this "come to" be natural to be with any other verbs like: - come to eat - come to love - come to study - etc. (Not as "to come" as a physical move to arrive somewhere)

'However' and 'Therefore' are formal than 'But' and 'So' in casual conversation?