例句與造句

1. One container is holding cesium 137 while the other two contain cobalt 57.
2. The reason is clear, however : The instrument is powered by a tiny capsule of cobalt 57, a radioactive element that decays with a half-life of nine months; thus, Squyres explained, it's logical that by now, after 10 months, only half the cobalt 57 is left to do the job.
3. The reason is clear, however : The instrument is powered by a tiny capsule of cobalt 57, a radioactive element that decays with a half-life of nine months; thus, Squyres explained, it's logical that by now, after 10 months, only half the cobalt 57 is left to do the job.
4. It's difficult to find cobalt 57 in a sentence. 用cobalt 57造句挺難的