that 引导从句 什么时候可以省略掉that

that\u5f15\u5bfc\u7684\u5404\u7c7b\u4ece\u53e5\uff0c\u54ea\u4e9b\u60c5\u51b5\u4e0b\u80fd\u591f\u7701\u7565that\uff1f

\u3000\u3000\u5bbe\u8bed\u4ece\u53e5\u4e2d\u7684that\u53ef\u4ee5\u7701\u7565,\u5b9a\u8bed\u4ece\u53e5\u4e2d\u5047\u5982\u5f15\u5bfc\u8bcdthat\u5728\u4ece\u53e5\u4e2d\u5145\u5f53\u5bbe\u8bed,\u53ef\u4ee5\u7701\u7565.
\u3000\u3000\u4f8b\u5982\uff1a\u5bbe\u8bed\u4ece\u53e5\uff1aI promise that I will study hard.\u8fd9\u91cc\u7684that\u53ef\u4ee5\u7701\u7565
\u3000\u3000\u5b9a\u8bed\u4ece\u53e5 This is the factory that we visited yesterday.\u8fd9\u91cc\u7684that\u53ef\u4ee5\u7701\u7565
\u3000\u3000\u4f46\u662f\u5728\u8fd9\u53e5\u4e2d\uff1aThis is the factory that lies in Guangzhou.\u8fd9\u91cc\u7684that\u505a\u4e3b\u8bed,\u4e0d\u80fd\u7701\u7565.
\u3000\u3000\u4ee5\u4e0b\u60c5\u51b5\u4e0d\u53ef\u7701\u7565
\u3000\u30001.that\u5f15\u5bfc\u4e3b\u8bed\u4ece\u53e5\u3001\u8868\u8bed\u4ece\u53e5\u3001\u540c\u4f4d\u8bed\u4ece\u53e5\u65f6\u4e0d\u80fd\u7701\u7565
\u3000\u30002.\u5bbe\u8bed\u4ece\u53e5\u4e0d\u6b62\u4e00\u4e2a\u65f6,\u4e0d\u80fd\u7701\u7565 \u5982\uff1bthey
\u3000\u3000complain\uff08that\uff09they have to do homework from morning till night,that it
\u3000\u3000is hard to study good,that they are very tired.\u662f\u8fde\u7eed\u7684\u5bbe\u8bed\u4ece\u53e5\u65f6,\u7b2c\u4e00\u4e2a\u53ef\u7701,\u540e\u9762\u90fd\u4e0d\u884c.
\u3000\u30003.\u5bbe\u8bed\u4ece\u53e5\u4e0e\u4e3b\u8bed\u4e4b\u95f4\u6709\u63d2\u5165\u8bed\u65f6,\u4e0d\u53ef\u7701 \u5982\uff1athe teacher said,happy and firmly(\u63d2\u5165\u8bed),that we must do homework.
\u3000\u30004.\u5f15\u5bfc\u5bbe\u8bed\u4ece\u53e5\u662f\u4e00\u4e2a\u4e3b\u4ece\u590d\u5408\u53e5 \u5982\uff1ai belive that if i work harder,i will pass the exam. \u8fd9\u4e2a\u6709\u70b9\u96be\u5ea6,\u4e00\u822c\u4e0d\u4f1a\u51fa\u73b0\u6211\u60f3..

that\u5728\u4ece\u53e5\u4e2d\u505a\u52a8\u8bcd\u7684\u5bbe\u8bed\u65f6\u53ef\u4ee5\u7701\u7565\uff0c\u6bd4\u5982This a nice bag (that)my friend bought for me.that\u505abought\u7684\u5bbe\u8bed\uff0c\u6240\u4ee5\u53ef\u5199\u53ef\u4e0d\u5199\u3002

宾语从句中第一个可以（如果存在一个以上的并列宾语从句的话，第2个从句的that不能省略） 如 I think (that) you are smart.

定于从句中关系代词that在从句中担任宾语成分角色 如 That's just the thing (that)I want.

欢迎指正。

that引导的是名词性从句中的宾语从句

扩展阅读：只用that的7种情况 ... so that引导目的和结果 ... and that引导什么从句 ... as that 引导从句 ... that3 top试试这个 ... that if引导什么从句 ... it says that china ... all that引导的从句 ... 8个就近15个就远原则 ...