指出下列各句中句式与例句“此非孟德之困于周郎者乎”句式相同的句子（   ）

Some of the students have already learned enough English to ____ a conversation with a native English speaker.

I ______ along the road when I saw Peter. So we stopped and had a chat.

Not only Susan but also Sandy _________ abroad for traveling. They will return next Sunday.

Scientists still wonder whether cloningwill help or harm us and where it ____ us.