根据所提供的信息, 选择正确的答案。

Piano Player Wanted

Boys and girls, are you music fans? Can you sing or dance? Can you play the piano?

Welcome to our Sky Rock Band.

Please call Victor at 6891-3453 or give an email to music@yahoo. com.

                                                                                    Let's Learn Japanese

Can you speak Japanese? Do you want to learn Japanese? Come to the Japanese club（俱乐部）now.

Time: 9:00 a. m. -11:30 a. m. (from Monday to Friday)

Call Henry at 6543-1248.

Ping-pong Club

Do you like to play ping-pong? Do you want to play ping-pong well? Mr. Chen can teach you. You can come here every Friday afternoon.

Tel: 8623-1940

Add: Room 102 in School’s P. E. Building.

                                                                                                Wanted

Can you swim? Do you like children? Can you help them with swimming on weekends? Come here!

Call Jane at 8330-9785 for more information (信息).

如图为某钙片的商品标签，请根据标签的有关信息完成下列各题：

函数y=（m﹣n）x²+mx+n是二次函数的条件是（　　）

如图1所示，一株绿色植物在适宜光照下进行稳定光合作用，当B时大幅度降低光照强度，其叶肉细胞中五碳化合物（C₅）的生成、消耗速率发生了变化．请回答相关问题．

（1）在BC时间段内，三碳化合物的生成速率____ ，经历BC段之后，三碳化合物的含量将____ 

（2）如果D点之后大幅提高周围空气中的CO₂浓度，能否有效提高光合作用速率？____（填“能”或“不能”）．试述其原因：____ 

（3）将生长正常的该植物幼苗对称叶片的一部分（A）遮光，另一部分（B）不做处理（如图2所示），并采用适当的方法阻止两部分的物质和能量转移．在适宜光照下照射6小时后，在A、B的对应部位截取相等面积的叶片，烘干称重，分别记为M_A、M_B．若M=M_B﹣M_A，则M的确切含义可以描述为____