"That is their doctor."

Translation: 那是他们的医生。

[Thomas.Zach]

In what contexts can we drop the 个?

When am I allowed to simply write 那 for "That" instead of the full 那个?

[Malou972]

You have to put ge before a number

[CoachTomG]

Why is ge after na wrong

[Malou972]

Because their is no number after

[HerbalTeeth]

这个是他们的医生。was wrong, what does that mean? I thought "This is their doctor?"

[Telik2]

The English sentence asks for "that" (use of 那), not "this" (use of 这)

[Nemomeori]

Why is 那是它们的医生 not correct? Can't 'their' refer to animals? Or you don't use 们 with 它

[JesperWarn]

I think 它 means "it" so more like inanimate objects.

[raykrause]

Can it also be reverse order?

[NasuSamaruk0]

Reversing the subject with the object, we have 他們的醫生是那個, where 個 must be included to identify the type of object.

This type of sentence is not commonly said or written. It is most common to use the main one in the conversation.

[WillowsofXihu]

Also, 那位 would likely be used rather than 那个 in order to be polite, but this still sounds awkward compared to the original word order.

[hooplabric69]

When is 个 necessary and when is it not?

[gfceciliano]

Why is 那 and not 这?