It is written clearly in the requirements that all passengers _______ check onto board thirty minutes before the plane takes off.
Rather than ________ on a crowded bus , he always prefers ________ a bicycle.
When he came back, his wife was found _________.
Every minute should be made the most of ________ our lessons well.
Our English teacher recommended that we ________ an English dictionary.
I don’t think he is right, ________?