这道题是强调句还是定语从句?
例句：_Is_ was known to us all that Johnson had broken his promise _that_ he would give each of us a small gift.
框里面为什么不能填as；which?强调句不是去掉it's 和that 仍然构成完整句子的才叫强调句吗?这句话去了这两样就不是完整句子了呀.