python新手求解答，为什么运行不下去了

dic = { -1.7: '蓝莲花', -0.7: '演唱：许巍',0.0: '',
0.7: '没有什么能够阻挡', 6.01: '你对自由的向往',
11.43: '天马行空的生涯', 16.99: '你的心了无牵挂',
21.2: '', 22.63: '穿过幽暗的岁月', 27.81: '也曾感到彷徨',
33.13: '当你低头的瞬间', 38.32: '才发觉脚下的路', 42.37: '',
43.79: '心中那自由的世界', 49.5: '如此的清澈高远',
54.31: '盛开着永不凋零', 58.5: '蓝莲花', 65.41: '', 110.6: '穿过幽暗的岁月',
115.6: '也曾感到彷徨', 121.09: '当你低头的瞬间', 126.33: '才发觉脚下的路',
130.23: '', 131.55: '穿过幽暗的岁月', 136.93: '也曾感到彷徨',
142.21: '当你低头的瞬间', 147.62: '才发觉脚下的路', 151.64: '',
152.97: '心中那自由的世界', 158.23: '如此的清澈高远',
163.3: '盛开着永不凋零', 167.7: '蓝莲花', 173.95: '', 180.06: ''}

import time
t=0
u = iter(dic)
while True:
for i in u :
if i < t:
print(dic[i])
break
t += 0.5
time.sleep(0.5)