. Dolphins ___ communicate through a series of clicks and whistles.
A. can
B. could
C. able to
D. must

Random Topics:
Simple present/ past/ future tensePresent Simple x Present ContinuousAction vs Linking Verbs/ Verb PhrasesNoun PhrasesModal Verbs of PermissionHomophone & HomonymPreposition & GerundComparisionsPrepositions and Phrasal VerbsTenses of Verbs - UsageOther quiz:
Grammar › ViewPeople say that Linda’s family has a lot of money.
A. It is said that Linda’s family has a lot of money.
B. It was said that Linda’s family has a lot of money.
C. It says that Linda’s family has a lot of money.
D. It is said that Linda’s family have a lot of money.
Modal Verbs › View
She __________ have completed the assignment; it was due yesterday.
A. might
B. could
C. should
D. must
Modals in The Past › ViewThey ________________ (win) the football match, but John hurt his ankle.
A. could have win
B. could have won
C. should have winned
D. should have won
Conditional Sentences › View
If I _________________(not have) this terrible cold yesterday I ________________(do) my homework.
A. don’t have, will do
B. didn’t have, would do
C. hadn’t had, would have done