Even though it's completely fine and great and clear if you release the T here.

如果你在这里发 T 音就会很好很清楚发音。

His pronunciation is clear, but he has a heavy accent which makes him difficult to understand sometimes.

发音清楚，但有很重口音，这让有时理解困难。

For pronunciation, it's mostly clear, but not always clear; he would probably get 5.

发音大都是清楚，但不是总是很清楚，那么可能会得5分。

And you want to be in a place of power where you know that you pronounce things clearly depending on who you are speaking with.

如果你想做一个有力演讲，你知道你发音清楚取决于你和谁说话。