This is the follow-up on the original question:

Finally, I fix the problem. Now, the connecting point of the hose
doesn't leak any more. This is what I have done:

- Use the correct sized screw driver. This takes care of most of the
leak.

- Warm the hose with a hair dryer before tightening the screw of the
clamp. This takes care of the remaining tiny leak that the big screw
driver cannot take care of. Thanks for people who have suggested this
tip.

I don't need to use a telfon tapes, and I don't need a different type
of connector. Happy ending...

Jay Chan