Would you like some tea or coffee?
In this sentence, "would" is used to make a polite offer.
Other examples are:
Would you like some sake?
Would you like to see our facilities?
Would you like to take home one of our brochures?
"I have (just)" + past participle is used to explain an action or event that has happened in the recent past. To express something which has happened in the very recent past we use "just" as an option. In everyday conversation, native speakers usually say "I've" instead of "I have".
Other examples are:
I've just finished my weekly report.
I've spoken to the clients, and they say they need more time.
I've had to change my plans.
What do you think of it so far?
Mr. Shumacher has been in Japan only a few days and is probably going to stay longer. Mr. Yoshimoto wants to know Mr.Shumacher's impressions of Japan from the day he arrived until now. He uses "so far" at the end of the sentence to express this.
Another example is:
A: I've been working at KCRL for two months.
B: What do you think of it so far?
Have you had time to do any sightseeing?
This is a question asking about recent past news or events.
Please remember that the verb tense is the past participle.
Other examples are:
Have you finished your report yet?
Have you been skiing this winter?
Have you decided where to go for your next holiday?
You should go and see a place called Nanzen-ji...
In this case, "you should" + present simple is used to give someone advice. You can also use "ought to" in the same way.
Other examples are:
You should see "Titanic" - it's a great film.
You should listen to language tapes to improve your English.
You should go to Nagano if you're interested in hiking.
Could you write that down for me?
In this sentence, "could" + present simple is being used to make a polite request. Although "can" may also be used in this situation, "could" is more polite or more formal.
Other examples are:
Could you fax me last month's sales figures this afternoon?
Could you lend me 100 yen for the coffee machine?
Could you proof-read this document for me?
Well, shall we begin the meeting?
Mr. Yoshimoto is using "shall we" + present simple here to make a suggestion.
Other examples are:
Shall we go out for dinner this evening?
Shall we have a drink after the meeting?