Select all that apply: which sentences have a standard second-conditional clause pattern?
If the hill had less street lighting, the observatory would see fainter stars.✓Correct answer
If I understood that chess opening, I would play it confidently.✓Correct answer
If the hill would have less street lighting, the observatory would see fainter stars.
If I understand that chess opening, I would play it confidently.
Explanation
The observatory and chess sentences correctly combine past conditions with would results. The alternatives use would in an if-clause or attach a hypothetical result to a present-form condition.