[ TOEIC Grammar and Vocabulary Review ]
The researchers ………………….. hard to develop a perfect new model over the last two years.
A. work
B. worked
C. are working
D. have been working

Random Topics:
Gerunds in SentencesComparative AdjectivesPast Simple vs Present SimpleVerb AbilityGrammar - FragmentsWill or Going toWish, Unless, If sentenceTenses & PrepositionPast ContinuousTo Infinitive or Bare InfinitiveOther quiz:
Present Perfect Simple and Continuous › ViewJack _______________ in Melbourne for many years.
A. has worked
B. has been working
C. has worked/has been working
Tenses › View
Martha _____ the violin when she was younger.
A. used to played
B. was used play
C. used to play
D. usually play
Grammar › ViewI haven’t been to the beach the _______summer.
A. every
B. all
C. whole
D. each
Conditional Sentences › View
If I go on a diet
A. I’ll buy you some sweets.
B. I’ll lose weight.
C. we’ll go for a picnic.