[ Modals ]
Using lasers to produce extremely short and repeatable pulses of light, today scientists ———— events happening in time intervals as short as l.000 trillionth of a second.
A. must have measured
B. were measuring
C. used to measure
D. may have measured
E. are able to measure
Random Topics:
Past Simple and ContinuousConditionals and Modal VerbsPrepositions and TensesModals - Have to or ShouldConditional and Mix Conditional SentenceNo Excuse Words / Conjunction SOActive & PassiveConjunctivesTypes of PrepositionTransitive or Intransitive VerbsOther quiz:
Conjunctions › View_____ I got home, I checked my email.
A. when
B. while
Homonyms › View
Los Vegas is a great place to ___ but not always a place to win.
a. gamble
b. gambol
Is it a fragment or complete sentence?
Who likes to?
A. Fragment
B. Complete Sentence
Verb Tenses › View
Tim often ………………………milk when he was a boy.
A. was drinking
B. drinked
C. drank