Ⅲ.综合运用

Blood Type and Heart Attack

If a 50-year-old man goes to the gym regularly and always eats healthy food,it's i__1__for him to have a heart attack—right?No.New research suggests that one cause of heart attacks might be s__2__you can't even control:your blood type.

In a recent study,researchers compared data on more than 1,300,000 people.Overall,those with type A,B or AB blood were 9 percent more l__3__to have a cardiovascular event（like a heart attack）than those with type O blood.

Although it's not clear why blood type might increase your heart attack r__4__,researchers have a few guesses.People with types A,B and AB blood t__5__to have higher levels of blood-clotting proteins.That makes artery blockages—one of the main causes of a heart attack—more likely to o__6__.These people are also more likely to have higher cholesterol,researchers said.

In the future,researchers hope that studies will examine each blood type alone,as well as f__7__out why the link between blood type and heart attack risk might exist.

1.i____________2.s____________3.l____________4.r____________5.t____________6.o____________7.f____________