21 Spending______ Christmas in a foreign country with local people was really _____ unforgettable experience for me.
A \;an B\;\ C the; an D the; \
22 with an important decision, one that can affect his future, he doesn’t know what to do.
A. Face B. Facing C. To face D. Faced
23. I was leaving the office when it suddenly to me that I had forgotten my keys.
A. struck B. happened C. occurred D. hit