【题目】 is that they are creative and strong-willed. (common)
他们的共同之处在于他们都富有创造性且意志坚定。

【答案】What they have in common
【解析】 此句要用到主语从句和固定短语。分析句子is之前是主语从句，从句中缺少宾语，故用what；have in common是“有共同点”的意思。所以答案是：What they have in common。