Using demonstratives with time periods

Question

I want to express 'These past one and a half years...'. E.g. 'These past one and a half years have been really fun!'

What I've come up with so far is: この一年半間で。。。[past tense].

I think I've just made the mistake of literally translating it though.

Answer 1

It is 「この[一]{いち}[年半]{ねんはん}」.

You cannot add 「[間]{かん}」 to it, but you can 「の[間]{あいだ}」.

The "rule" is that we just cannot say 「～～[半間]{はんかん}」.

Correct:: 「この1年半」、「この1年半の[間]{あいだ}」、「この2[週間半]{しゅうかんはん}(の[間]{あいだ})」, etc.

Incorrect: 「この一年半[間]{かん}」、「この2週間半[間]{かん}」, etc.

「この」 can, of course, be replaced by 「その」 or 「あの」 depending on the context.