A short quiz to test your level of English and see where you need to improve.
passive voice-- past participle of forbid"
Explanation
interruption (the phone ringing) of an ongoing action (working in his office)
"at the moment" hints that the answer is in present continuous
last month--> past tense
in spite of= regardless of, in defiance of
invaluable = indespensable, of the utmost value, very useful
The "to" is the hint that the right answer is "got." If the right answer were "arrived," the preposition would be "at." "Reached" and "entered" would not be followed by a preposition, nor are they the best answers.