情态动词can/could表能力 — 英语词汇题
题目
根据句意及首字母提示，用情态动词 can/could（表能力）的正确形式和所给单词的适当形式填空。注意：can 表现在能力，could 表过去能力；can 后接动词原形。1. Guide dogs c______ help blind people cross the road safely. 2. When Tom was a child, he c______ not swim, but now he swims very well. 3. Elephants have a good memory—they c______ remember routes for many years.