少了一项

（每道题开头都有同一段：六个来源 SOURCES，每项是 (名字, 要等的秒数, 字节数)；fetch(name, wait, size) 睡 wait 秒后交回 size——「等」的时候别人能干活。）

（这一节的 fetch 多了一条：来源是「天气」时会抛 ValueError——线程里的异常怎么处理，就看它。）

work 自己 try/except：成功放 ("好", 名字)，失败放 ("错", 名字)。看几好几错、错的是谁：

import threading, time

SOURCES = [("首页", 0.05, 1200), ("新闻", 0.08, 3400), ("图片", 0.03, 8800), ("视频", 0.10, 20000), ("论坛", 0.06, 2600), ("天气", 0.02, 300)]

def fetch(name, wait, size):
    time.sleep(wait)
    if name == "天气":
        raise ValueError("来源挂了：" + name)
    return size

results = []
lock = threading.Lock()

def work(name, wait, size):
    try:
        r = fetch(name, wait, size)
        item = ("好", name)
    except ValueError:
        item = ("错", name)
    with lock:
        results.append(item)

ts = [threading.Thread(target=work, args=s) for s in SOURCES]
for t in ts:
    t.start()
for t in ts:
    t.join()
good = sorted(n for k, n in results if k == "好")
bad = sorted(n for k, n in results if k == "错")
print(str(len(good)) + "/" + str(len(bad)) + "/" + ",".join(bad))