A.excellent
B.excuse
C.explain
D.express

A. Was it serious
B. Did you see the doctor
C. Are you feeling better now
D. How are you
E. Take more exercise and keep healthy.
F. What was the matter
G. I miss you so much.
H. You are so strong.

A. were put forward due to scientists’ recommendations
B. came into being as a result of the workers’ demand
C. were introduced because quite a number of people were killed or seriously injured
D. were effective enough to protect workers and customers