Read the sentences. when bricking a building, masons must fit the bricks together. sometimes, masons slice bricks in half for a better fit. which is the best way to combine the sentences? when bricking a building, masons must fit the bricks together; sometimes they slice bricks in half for a better fit. when bricking a building: masons must fit the bricks together; sometimes they slice bricks in half for a better fit. when bricking a building, masons must fit the bricks together; sometimes they slice bricks in half for a better fit.

The best way to combine the sentences is "When bricking a building, masons must fit the bricks together; Sometimes, they slice bricks in half for a better fit."

Explanation:

The best way to combine the sentences presents the use of commas and a semicolon.

The first comma follows the rule of "Use a comma after a dependent clause that starts a sentence", then "When bricking a building," is the depending clause.

The semicolon follows the rule "to link (in a single sentence) two independent clauses that are closely related in thought" both sentences are talking about the same process, then "... the bricks together; Sometimes, they slice bricks..." is the merge of the two sentences into one.

The second comma follows the rule "Use a comma after introductory adverbs". Sometimes is a frequency adverb, then "Sometimes, they..."

i used to know but i learned it a long time ago sorry

explanation:

the correct answer would be:  

a. adverb phrase