A punctuation question with the same word in every choice tests which sentence parts belong together. Read across the blank and test the sentence before the mark: a colon or a single dash introducing more detail needs a complete sentence before it. Then name the parts on both sides and ask whether the later words finish the earlier ones. A comma can set off extra information, but it can't separate a word from the words that complete it.
Hints
- Hint 1
Look at the words immediately after the blank. What do they tell you about the exercise routine?
- Hint 2
Now check whether the word at the blank needs those words to finish its meaning. Decide that from what the sentence says about the routine, rather than where you might pause.
Step-by-step
Test the marks, then connect the words
Step 1Test the colon and dash
Read astronauts follow a strict exercise routine, then add the shared word lasting. Can we stop there? That word starts a description that still needs to say how long the routine lasts, so the words before the mark are unfinished. A colon and a single dash introducing more detail each need a complete sentence before them, so neither belongs here.
- Step 2
Find what finishes the description
What do the words after the blank add to lasting? The phrase about two hours each day tells us how long the routine lasts, so these words finish its meaning. They're part of the phrase describing the exercise routine, not a separate comment that can be set off.
- Step 3
Keep the description together
A comma can't split a word from the words that finish it. Read lasting about two hours each day as one unbroken phrase, so no punctuation belongs at the blank. Use lasting without a mark after it. Choice D.