call on shares

You can call your broker and say, I'd like to short stock number one and what the broker will do is borrow the shares on your behalf and sell them and then you own negative shares.

你可以打电话给你的经纪人说，我要做空一号股票，经纪人就会在你的名下赊入这些股票，然后卖掉，这样你就拥有数量为负的股票了。

Call options give investors the right, but not the obligation, to buy shares of a company at a specified price on a certain date.

认购期权给了投资者在某日以一个特定价格购买一家公司股票的权利，但他没有义务非要购买。

If the stock market plunges and you own shares on margin, you could receive a margin call from your broker, asking that you add more cash or securities to your account.

如果股市下跌，而你拥有通过保证金购买的股票，你就会收到经纪商追加保证金的要求，让你向帐户中追加资金或是股票。