If she _______________ how to calibrate the instrument, she _______________ done the experiment.
(A) knows, will have
(B) knew, had
(C) had known, could have
(D) should have known, would have
Explanation: A)knows, will have //Present ,future
B)knew, had //past past
c)had known, could have//past perfect,perfect conditional
D)should have known, would have //present,future
In a Type 3 conditional sentence, the tense in the ‘if’ clause is the past perfect, and the tense in the main clause is the perfect conditional or the perfect continuous conditional.
|If clause (condition)||Main clause (result)|
|If + past perfect||perfect conditional or perfect continuous conditional|
|If this thing had happened||that thing would have happened.|
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