地球上最大的生态系统是（ ）

“发展才是硬道理”、“特区姓‘社’不姓‘资”’的观点出自（　　）

下列实验操作正确的是（　　）

阅读下面这首古诗，回答后面题目。
                                                                                                    不见
                                                                                                    杜甫
                                                                                      不见李生久，佯狂真可哀！
                                                                                      世人①皆欲杀，吾意独怜才。
                                                                                      敏捷诗千首，飘零酒一杯。
                                                                                      匡山②读书处，头白好归来。
     【注释】这首诗写于客居成都初期，杜甫此时辗转得悉李白已在流放夜郎途中获释，遂有感而作。①世人：指统治集团的人。②匡山：李白少时读书的大匡山，在今四川北部。

Nowadays the belief has become general ________ sea food and fruits rich in vitamin C should never be eaten at the same meal.