Any employee wishing to leave the workplace for any reason during business hours must （） a special leave form.

单项选择题Our new range of products is available in （） configurations, including sports and commercial styles.

A.vary
B.variety
C.variable
D.various

单项选择题The chief executive officer is particularly （） that recent staff surveys have shown a severe drop-off in employee satisfaction.

A.concern
B.concerns
C.concerning
D.concerned