1.Experts on the moon have been speculating on what is behind the flashes.
speculate 猜測;推測
It is useless to speculate why he did it.
對他為什么這么做妄加猜測毫無用處 。
2.The so-called transient lunar phenomena have been known since the 1950s, but they have not been sufficiently observed.
sufficiently 充分地
Unqualified members of staff at the hospital were not sufficiently supervised.
醫院里一些還未取得資格的員工沒有受到充分的督導 。