[ Past Tenses ]
They __________ (debug) for two hours before they found the error.
A. debugged
B. had debugged
C. were debugging
D. had been debugging

Random Topics:
Simple, Compound, Complex SentencesPlaces in TownContractions and ConjunctionsPersonal PronounsClauses and ConjunctionRelative Clauses & Real ConditionalsPresent Perfect vs Past SimpleAsking & Giving OpinionCountable QuantifiersWho am I?Other quiz:
Grammar › ViewThey reached home in ___ hour.
A. an
B. a
C. the
Some/any/every/no + Body/thing/where › View
It is too noisy here. Can we go _____ else to discuss the homework?
A. Everywhere
B. Anything
C. Something
D. Somewhere
What is the positive degree of ( Taller ) ?
A. most tall
B. more tall
C. tallest
D. tall
Modal Verbs › View
The noise from the trains __________ me terribly last night.
A. was annoyed
B. annoyed
C. has annoyed
D. had annoyed
