英语强调句时态问题!请问强调句是不是前后事态一定相同啊,比如前面是it is ...that 后面就不能出现过去时呢

强调句:what is it that makes them so unhappy? 这个是强调句?是不是强调句的疑问句 It is...that 强调句的问题 It is .that ..会出现在几种情形里?比如：强调句.或者其他什么从句（选项中常常作为迷惑强调句的）?ps ：强 It is obvious that he tries his best.是强调句吗 是强调句吗 强调句是倒装句吗请问,强调句是不是倒装句来的,例如 It's he who come in.is 和 he 是不是倒换位 强调句,It is adj that 关于It is.that 的强调句 英语翻译 强调句it is ...that it is only when.that.强调句 it is强调句接人时后面用什么连接句子（who or that） it was/is ...that/who...是强调句,但? it is not until...that是强调句吗