It depends on what your book is going to be about! My advice is to stop worrying about some sort of perfect first sentence and just write your book -- then you can go back and figure out a great first sentence based on what you have written.
If you capitalize the first letter of the sentence and place a period at the end, use an apostrophe for the contraction for 'it's', it is a correct sentence: It's going to be a great night today. Although correct as a sentence, it would make more sense if it said: It's going to be a great night tonight.
The grammar depends on the meaning of the sentence. If it is talking about the future, it would be, 'This will be a great adventure'. If it is talking about something that has already happened, it would be, 'This would have been a great adventure.'
My assets are great. It would be an asset to me if you did that.
My husband will accompany me to the function tonight.
Nice, pleasant, heart-warming, dreadful, and frightful are words that could replace great in the example sentence provided above.
Chimpanzees are very smart, for example...they can recognize their own reflection in a mirror, while other animals would not be able to.
If speaking about a grandmother and great-grandmother, yes, lower case. But when writing to your grandmother, it would be upper case. Also, if either is the first word of a sentence it is first-letter uppercase.
Answer: No. They would not.
absolutely not. if it did it would get killed
hell no
The complexity of this question is to great for an adequate answer
I would say that this is a great example.