多长时间

• how long

例句

1. 你独自一人在教室里多长时间了？
   How long were you by yourself in the classroom?
2. 做这项工作需要多长时间？
   How long will the job take?
3. 安装电话机与总机接通要多长时间？
   How long will the connection of the telephone take? ie How long will it take to install a telephone and connect it to the exchange?
4. 自从我们看望你母亲以来到现在有多长时间了？
   How long is it since we visited your mother?
5. 我回忆不起来多长时间了。
   I can't recall how long it has been.
6. 你能瞪着看多长时间不眨眼？
   How long can you stare without blinking your eyes?
7. 到那儿要多长时间？
   How long will it take me to get there?