为研究人的活化辅助T细胞对B细胞产生抗体的影响，研究人员将来自于同一豚鼠的B细胞等分为三组．每组培养液中加入的细胞种类如下表所示（“+”表示加入该细胞，“一”表示未加入该细胞）．

将三组细胞在相同条件下培养，在第2、4、6、8、12、14天分别检测A、B、C组上清液中的抗体含量．实验结果为：C组没有检测到抗体，A、B组的结果如图所示．

（1）实验的对照组为____ 组．实验结果显示，B组可从第____ 天起检测到抗体．

（2）A组与B、C组结果相比较，说明____ 不能刺激B细胞活化．

（3）B组与C组结果相比较，说明活化辅助T细胞能____ 

下列各句中，没有语病的一句是(　　)

“人要学会走路，也要学会摔跤，而且只有经过摔跤才能学会走路。”这句话告诉我们 （   ）

    Jack Ma is the founder and CEO of the alibaba.com,____ is the biggest e-commerce company in China. The website is an English-language site. It aims to offer suppliers and consumers____ direct means to communicate, and thereby save time and money ____ (efficient). This model of business ____ (refer) to as B2B (business to business), and it has attracted millions of users worldwide. On the back of this success. Jack Ma and his team developed Taobao in 2001. Today, alibaba.com is considered by many to be one of the best B2B____ (site), with over 7 million users____ (come) from more than 200 countries and religions. Jack Ma____ (become) the first Chinese businessman to appear on the cover of the famous magazine Forbes in the past 50 years. Jack Ma is respected by people not just because of his success, but also because of his____ (person). Although modest, Jack Ma is a very ____ (ambition) man. When asked about his future plan, he once said, 'I believe that in the next ten years, ____ the top three Internet companies in the world, one will be from China—and we want to be that company.'