As was touched upon by my fellow members, here is my belated version.I would like to tell you my two impressions.
Firstly, a phonetic sign. I realized that I have misunderstood a phonetic sign. That is a ː. Prof. Mastusaka told us this sign does not mean a sound length. The fact made me surprised. I thought the important point of the pronunciation, for example between “sheep” and “ship” is the length of sounds but he told us that is not the case.
Secondly, the phonemic difference between cards and cars. Actually, this was so difficult for me. I was able to double-check the difference, thanks to what Prof. Tanabe and Prof. Matsusaka again.