It might be better to type all your text then add the links later selecting the words you want to use.
It's usually because the cursor is inside the closing </a> so as you type text it gets added to the hyperlink.
You can do what Ant said, or you can add something after the text to be hyperlinked, i.e. another word or white-space or punctuation, anything that will allow you to "escape" from the <a> tag using the cursor keys.
You can also change to HTML view and edit the generated HTML manually if you wish.
You expect me to remember? Sheesh. I'm lucky I remember to post at all.
(I am well aware some wish I wouldn't.)
If I've already moved the cursor, why is it staying inside the </a> tag?
Maddening.
If you didn't post your nonsense we wouldn't have much to talk about these days ;)
If you lot didn't argue my cogent, well thought-out treatises with nonsense, I'd always be talking to myself.
Even though our cultures are similar, there are too many differences in daily life for it to be possible for Americans and Britons to always agree on issues, or even to often agree. It does make for interesting discussion though on some topics, and I genuinely do like to hear opposing views on things, particularly on hot button issues.
Because at a guess the </a> is the end of the line / text?