当匆遽修饰的次是 all, anything, everything, nothing, littler, much, some时, 无论关系代词作主语还是宾语, 多用that, 做宾语时 that 可省略.
For example:
All (that) i want is peace and quiet.
This reference book contains much (little) that is useful.
The journal reports everything that happens in the area.