Question

why did colonists need to stop tea from being unloaded from three ships docked in boston harbor in december of 1773?
dock workers in boston were on strike.
the tea was supposed to be unloaded in philadelphia.
a tax would have to be paid once the tea was unloaded.

Explanation:

The colonists were protesting the Tea Act of 1773, which imposed a tax on tea. If the tea was unloaded, the tax would have to be paid, so they tried to prevent the unloading to avoid paying the tax.

Answer:

A tax would have to be paid once the tea was unloaded.