What is the punctuation error in this sentence help

The ancient Romans burned coal in Britain:the ancient Chinese may have used it before then

Imagine that you are putting together a time capsule for future generations. it will be buried and then unearthed in the year 3000. you want to place in it the items you feel best document your life and times. they can be personal items or items that relate to your larger community. name six items you would include. they can be objects, writing, or something in an audio or visual format. what would you include and why? describe each item in one or two sentences mentioning what it is and how it could future generations learn about your life and times.

When did martin luther king, jr. deliver his famous "i have a dream" speech? a. during the montgomery bus boycott b. during the birmingham campaign c. during his acceptance of the nobel prize d. during the march on washington

The explorer marco polo who visited china was from barcelona luxembourg rome venice