@98future,
Quote:other is also easy for me, but after "er"sound in "other", i have to take back my tongue to my mouth, then for "then" i have to stick out again, and so does'that". It would be so hard...... especially when I want to speak fast
'other than that'
There's no need to retract the tongue.
From your initial "I know how to pronounce "th", which requires me to stick out my tongue between my front teeth",
you may very well be sticking your tongue out much too far to make the 'th' sound. We do of course extend it further for very emphatic th's, but for most th's the tongue doesn't go past the front top teeth at all.