The scientists _______ on the experiment for six months before they finally _______ a breakthrough last Tuesday.
Show Worked Solution
Worked Solution
Step 1: Six months of ongoing effort before a past event — past perfect continuous (had been working) emphasises the extended duration leading up to the breakthrough.
Step 2: Last Tuesday signals the breakthrough was a completed single past event — simple past made.
Answer: had been working / made
Correct answer: had been working / made
Want more questions like this? Superholic Lab has 10,000+ MOE-aligned questions with full worked solutions.
Start Free Trial — 7 Days Free