After waiting for forty minutes, I heard some noise in the outer room.
等了40分钟后，我听到了外边房间的什么声音。
2
For one, nascent stars are incredibly active and their changing outer atmospheres can at the very least make for background noise.
比如，新生恒星是异常活跃的，它们不断变化的外层大气至少会导致背景噪声。
3
The algorithm employed ellipsoidal outer approximation of the feasible set assuming instantaneous process and observation noise vectors and the initial state to be bounded by known ellipsoids.