Two of your friends have been secretly dating each other. Finally they tell you about it, and you're really surprised because you didn't suspect it. You say:
I was completely oblivious!
academic, adverb, collocations, dating, 日本語サポート 
You're an architect. You're showing a couple an early version of the floor plans for their new house. It's easy to make changes to the plans now, but if they want to make changes later it will be difficult and expensive. So you say:
If you have any questions or concerns, now is the time to bring them up.
collocations, discussion, phrasal verb, questions, time You bought a cheap bottle of wine, but you actually liked it. You are telling your friend about this wine. You say:
I was pleasantly surprised.
collocations, reviews, surprise You're writing a report about a company. It is #1 among companies of their type. You are introducing the company at the beginning of your report, and write:
They are widely recognized as the world's leading solar energy company.
#1, business, collocations, companies, written English 