What type of punctuation is not used internally in a sentences

Which is a higher ratio, 6: 9 or 3: 7

Iback to my office after i saw the rain.

Which persuasive technique is used in the passage below? after seeing ads for greasy french fries, sugary soft drinks, and salty chips, you head to the kitchen to fix yourself an enormous (and unhealthy) snack. with the tv blaring in the background, you then waste hours on the web.