The time Dr. Wang has devoted _____ the disabled in the past five years is now considered_____of great value.
The engineer ________ my father works is about 50 years old.
They arrived at a farmhouse,in front of ________ sat a small boy.
The pen ________ he is writing is mine.
Can you lend me the book ________ the other day?
At the party,John made up a joke,________ people burst out laughing.