下面语段中画线的成语，使用不恰当的一项是(　　)静默了半年多的姚明面对大庭广众宣布:告别NB

Never visit strange websites, ________ the thieves may crack(破译)the password of your Internet account.

If you prefer the red evening dress, you’ll have to pay ________ 30 dollars, because it’s made of silk.— Ok. Here you are.

So many women take up walking as a regular form of exercise every day, which, of course,isto their health.

Of the 2,000 stock investors______last month,90% was found_____in financial knowledge[ ]