A punctuation question with a transition tests where sentences end and which sentence the linking phrase belongs to. Cover the transition and split, then ask whether each side can stand alone. A period or semicolon separates full sentences; a pair of commas sets off a transition within one sentence. Then test the transition’s meaning to decide which sentence it belongs to. It takes a comma after it when it starts a sentence and before it when it ends one.
Hints
- Hint 1
Focus on the sentence about ring width and the part that starts with drought. Find the subject and main verb on each side of the blank.
- Hint 2
Ask how the drought and rainfall details relate to the weather claim. That tells you which sentence should carry the linking phrase.
Step-by-step
Cover, split, and place the transition
Step 1Check whether both sides can stand alone
The width of each ring depends on the weather is followed by the drought and rainfall details, so we’re checking how to punctuate the link between them. Cover for example and fill in formed: can each side stand alone? The first side has width as its subject and depends as its main verb; drought often produces thinner rings has drought and produces. The while clause adds what rainfall does, so there are two full sentences.
- Step 2
Remove versions that fail to separate sentences
Which versions can separate the weather claim from drought often produces thinner rings? Commas around for example leave a comma splice, two full sentences joined by only a comma. Using formed without any punctuation leaves a run-on, two full sentences placed together without a joining word or a separating mark.
- Step 3
Place and punctuate the linking phrase
For example means here is a case that shows the point; does it fit at the start of the drought sentence? Yes: drought often produces thinner rings, while ample rainfall produces wider ones shows how weather affects ring width, so the phrase starts the second sentence. At the start of a sentence, the phrase needs a comma after it, so the version with no comma after for example is missing that required comma. The version with a semicolon before the phrase and a comma after it separates the sentences and sets off the phrase. Choice B.