The management has assured all staff that anyone （） the professional development seminars will receive a certificate thanking them for their participation.

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

A.sign
B.signs
C.to sign
D.was signed

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