At 8 o'clock yesterday I ( had _ was having-had had -have) dinner with Mark.​

was having/had

Explanation:

it depends on the context outside of it to. For example if you were telling a story and that was a detail it would be "was having" but any other context would be "had"

taking into account that a theme is the central topic a text treats and can be developed through a story, play, poem etc. the following are themes that can be further developed:  

my best friend jeffrey has many unusual interests. (the story could be about each of the unususal interests)

once a man gives his soul over to evil, he can never go back. (this could be a saying or a proverb)

the three sheepdogs lay around the yard all day. (it could be developed detailing how each of these sheepdogs lay around)

a priest's collar has an unusual effect upon people. (it could be developed detailing the different effect upon people)

innocence is a powerful force in a world full of corruption. (it could be developed detailing how is a world full of corruption)

king lear is a play shakespeare wrote later. (it is just a sentence and doesnt give any idea or topic to be discussed in details.

evil often wears the disguise of innocence. (this could be a saying or a proverb)

based on the biblical principle philippians 4: 13 "i can do everything through christ who strengthens me." i agree that it is through him that we are given the strength to cope with every situation.

and based on the biblical principle proverbs 16: 32 "better to get angry slowly than to be a hero. better to be even-tempered than to capture a city."   i agree with the author of the passage to the extent that the nobility of heart demonstrates the strength of a person. those who are contemptuous, get angry easily and show their anger toward others are really weak, but those who are noble and make sure to not hurt other people and their feelings are strong people.