Unfortunately, it was in Yushu County, ______ a 7.1-magnitude earthquake happened on April 14, 2010, ______ a large number of students were buried inside damaged schools.
. He made _____ known to his friends that he didn’t want to enter politics.
. It used to be thought _____ the Earth was flat.
. In the west, people make _______ a rule to send Christmas present to their relatives and friends.
. _______ is well known, _______ Hong Kong returned to China on July st, .
. _______ was known to them all that William had broken his promise ______ he would give each of them a gift.