27. "Celebrate!"commanded the ads for the arthritis drug Celebrex,before we found out it could increase the risk of heart attacks.

【分析】多重复合句。主句为the ads for the arthritis drug Celebrex，谓语为commanded，宾语为"Celebrate!"。Before引导时间状语从句，其中又包含省略that的从句it could increase the risk of heart attacks作found out的宾语。

28. But what we forget-what our economy depends on us forgetting-is that happiness is more than pleasure without pain.

【分析】复合句。what引导主语从句作句子主语，破折号之间的what从句是对前面主语从句的补充；is是系动词；that引导表语从句，其中more than意为“不仅仅”。
【译文】但是我们所忘记的——我们的经济指望我们忘记的——是幸福远不止是没有痛苦的快乐。