Mary is a little girl. She is only four. She is not at school. She doesn't know how to read or write. But her sister Joan is a schoolgirl. She is ten years old. She knows how to read and write. One day, Joan sees her little sister in the room. She's at the table. There's a pencil in her hand. She's writing. “What are you writing, Mary?” She asks. “I'm writing a letter to my friend Rose. ” “But you don't know how to write. ”says her sister. “Well,” says Mary, "it doesn't matter. Rose doesn't know how to read. "

研究表明某流感病毒细胞的直径约为0.00000156m，用科学记数法表示这个数是（    ）

下列作品中，属于法国文学家写的有（     ）
①《约翰·克利斯朵夫》②《静静的顿河》③《等待戈多》④《钢铁是怎样炼成的》