Malaysia Airlines Flight MH370 was expected to land in Beiji

Malaysia Airlines Flight 370 ___________ course and turned back toward Kuala Lumpur -- but there were no indications from the pilot that he was doing so.

A．must have changed	B．could have changed
C．might have changed	D．should have changed.

Malaysia Airlines deeply regrets that MH370 ended in the southern Indian Ocean. MH370 first d_小题1:___ in the early hours of March 8th, while flying from Kuala Lumpur to Beijing.
We should know how to s__小题2:__ ourselves when the crash happened. Australian professor Galea, summed up 6 golden rules after years of research. It might be able to help you escape in case of emergency.[来源:学科网]
S__小题3:__ 1985, Australian professor ED Galea has interviewed 2,000 survivors of 105 plane crashes, searching for the keys to survival.
First, if you are traveling in a f ___小题4:__ group, you should insist that the airline does not separate （分开）you throughout the aircraft. Why? It’s natural that if you’re involved in that kind of situation that you’re going to want to meet the family before you move out.
Second, how do you untie your seat belt in a plane? You press a button. If you can’t untie your seat belt, then, you can’t run away and your c__小题5:__ of survival will drop.
Third, sit within seven rows of an exit and count exactly how many rows you are from the nearest two exits. Count so that you can find an exit in the d___小题6:__.
Fourth, we would all be safer if airline seats faced backward. But the difficulty with this is that the most of the tourists don’t like t__小题7:__ with their back facing the direction of travel.
Fifth, “Smoke is h__小题8:__ to your health. If you take in enough of them, you will die,” explains Galea. You must learn how to use a smoke mask. Otherwise, you’ll waste time trying to put it on -- time that could be used for running a __小题9:__.
At last, listen to the preflight briefing（飞行前的注意事项） by the flight attendants and read the s__小题10:__ instructions. Always be prepared. Good luck to you.

If you absolutely want to get the truth of Malaysia Airlines MH370, _______ wait until the timing is right.

A．at best

B．at all

C．at least

D．at most