[ Grammar ]
The robot manufacturer had his customers ___ their outdated robots.
A. exchange
B. exchanged
C. to exchange
D. exchanging

Random Topics:
Sentences Function and StructureIndependent ClausesSynonymArticles and QuantifiersTransitionsHave to / Do not have toPresent Simple and Present Continuous TensesSubject Verb Agreement & Subjunctive MoodModals and Adjectives (ed-ing)Social Media VocabularyOther quiz:
Tenses › View_____ tea is too sweet for me.
A. a
B. an
C. the
D. –
Grammar › View
Would Tom like some help with his presentation or can he manage by _____?
A. himself
B. alone
C. him
D. his own
Tenses and Conclusions › ViewWhich of these sentences uses the present progressive tense to describe an action currently in progress?
A. The train will arrive at the station soon.
B. They are discussing the new project at this moment.
C. She discusses the project with her team often.
D. They will be discussing the new project later today.
Modal Verbs › View
We ________ take an umbrella. It looks like it will be rain.
A. could
B. should
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D. would
