[ Grammar ]
Scientists now know that the lack of an embryonic thumb in birds is why ____ almost impossible for birds and dinosaurs to be related.
A. is
B. it is
C. is it
D. it

Random Topics:
Toeic VerbVerbs, Tenses, and VocabularyModals, Phrasal Verbs, Gerunds and InfinitivesWill & Be going toModal "Have to"Simple and Compound SentencesComplex SentencesCoordinating Conjunctions and Comparative AdjectivesSecond Type ConditionalAdverb of TimeOther quiz:
Grammar › ViewWhat is the preposition?
Singing is fun during the holidays.
___
A. is
B. fun
C. during
D. on
Grammar › View
You shouldn’t ________________________ go camping unprepared.
A. never
B. any
C. ever
D. nenenver
Adverbial Clause, Noun Clause › ViewThe virus spread ___ fast that everyone being sick at the same time.
A. so
B. such
C. too
D. enough
Conjunction › View
Everybody likes him because he is nice …………. helpful.
A. and
B. But
C. since
D. or
