题目

I have many pen pals in many countries. Do you know the girl on the bike in the photo? She is one of my pen pals. Her name is Reiko. She is a Japanese student. We are the same(相同的) age - 13 years old. She lives in Tokyo. She has two brothers. They live with their parents.    I like Reiko very much. But I don't know Japanese, and Reiko doesn't know Chinese, either(也). But we know English. So we write letters in English. Sometimes(有时) we talk on the phone. My favorite subject is math. Her favorite subject is music. We have the same hobbies. We like seeing comedies, playing 滴水法测重力加速度的过程是这样的：让水龙头的水一滴一滴的滴在其正下方的盘子里，调整水龙头，让前一滴水滴到盘子里面听到声音时后一滴水恰好离开水龙头，测出n次听到水击盘的总时间为t，用刻度尺量出水龙头到盘子的高度差h，即可算出重力加速度．设人耳能区分两个声音的最小时间间隔为0.1s，声速为340m/s，则A.重力加速度的计算式为2hn2/t2B.重力加速度的计算式为2h（n-1）2/t2C.水龙头距盘子的距离至少为34mD.水龙头距人耳的距离至少为34m