[ Modal Verbs ]
Scientists fear that a patient’s immune system _____ stem cells unless they _____ genetically identical to the patient’s other cells.
A. may reject / are
B. may have rejected / were
C. could reject / had been
D. has rejected / has been
E. would be rejected / were
Select your answer:
Random Topics:
Prefixes SuffixesRegular and Irregular AdverbModal Verb, Passive VoiceConjunctivesVerb, Object, PrepositionPrepositions and AdverbsCountable - UncountableTenses, Determiners & Subject Verb AgreementAdjective ClausesOther quiz:
Modal Verbs › ViewWe __________ (must / could) go to the meeting if we want to discuss the new strategy.
A. should
B. must
C. can
D. might
Grammar › View
Don’t believe him; he ______.
A. is obviously lying
B. lies obviously
C. obviously has lied
D. obviously had lied