[ Grammar ]
What the problem is ………………by tomorrow.
A. will have discovered
B. has been discovering
C. being discovered
D. will have been discovered

Random Topics:
Communicative GrammarPassive Voice and Modalstoo / enoughModal RequestsRelative Clauses and etcPossessive Nouns with Apostrophes and PronounsParts of SpeechPhrase or ClauseLinking Words and PhrasesPresent and Future TensesOther quiz:
Relative Pronouns › ViewThe heavy storm is the reason ………..I couldn’t go to school yesterday.
A. why
B. which
C. when
Modal Verbs › View
She _______ told me the truth earlier; now it’s too late.
A. shouldn’t have
B. should have
C. might have
D. could have