在搜索时使用问号作为通配符可以匹配任意单个字符。

Using a question mark as a ___wildcard can match any single character in your search.

疫情成为了今年经济预测中的最大不确定因素。

The pandemic has become the biggest ___wildcard in this year's economic forecast.

在这副牌中，小王是万能牌，可以代替任何一张牌使用。

In this deck, the joker is a ___wildcard that can substitute for any card.