流行病学的三个范畴：①描述、②分析、③（）。

个人情绪对事故的发生产生很大的影响。

Exercise is _______ as any other to lose unwanted weight.[ ]

A.such useful a way

B.so useful a way

C.as a useful way

D.as useful a way

In America, Virginia Beach has all the elements of a classic seaside resort: brilliant beaches, a lively boardwalk, plenty of restaurants and nightspots, and amusement rides are sure to appeal to kids. Many believe Virginia Beach is at its best in the off-season, when the town is less crowded but the weather is still mild.

Meanwhile, some safety tips should be followed, enjoying the happiness and excitement the beach offers.

The number l safety tip concerns ocean safety: pay attention to Flag conditions posted on the lifeguard stands. Lifeguards post a red flag to warn when the ocean water is dangerous. Take them seriously! Tourists from land-locked regions are particularly easily attracted by the magic of the waves. However, a calm ocean can become risky without warning. Make sure you swim near a lifeguard. Swimming without lifeguard protection is almost five times as great as drowning at a beach with lifeguards.

Never swim alone. Many drownings involve single swimmers. When you swim with someone else, if one of you has a problem, the other may be able to get help, including signaling for assistance from others.

Don't fight the current. The facts show that some 80% of rescues by lifeguards at ocean beaches are caused by currents. These currents are formed by surf and gravity, because once surf pushes water up the slope of a beach, gravity pulls it back. This can create concentrated rivers of water moving offshore. If you are caught in a rip current, don't fight it by trying to swim directly to shore. Instead, swim parallel to shore until you feel the current relax, then swim to shore. Most rip currents are narrow and a short swim parallel to shore will help bring you to safety.

小题1:When coming to Virginia Beach, children can enjoy the happiness of     .

A．walking on the road made of wood

B．joining the nightspots

C．having interesting rides

D．skiing in the sea小题2:Many people believe the best time to visit Virginia Beach may be     .

A．after autumn school term beginning

B．in the slimmer vacation

C．during the Christmas holiday

D．in the cold winter小题3:Swimming in the sea you'd better not swim     .

A．with a friend

B．within the sight of the lifeguard

C．with the current

D．as far as you like小题4:From the passage, we can know     .

A．one in five persons swimming in the sea is drowned

B．if one with lifeguard were drowning, five persons without lifeguard would be

C．some 80% people drowning by the currents are rescued by lifeguards

D．some 20% drowning by the currents are rescued by life guards小题5:The passage mainly tells us      .

A．some safety tips when swimming in the sea

B．the happiness and excitement the beach offers

C．Virginia Beach has all the elements of a classic seaside resort

D．the dangers for tourists from land-locked regions to swim in the sea

在民间人们还喜欢在窗户上贴上各种剪纸——（）花。

患者因缺铁性贫血给予口服铁剂治疗，治疗有效时一般用药多长时间网织红细胞升高( )

A．20天以上

B．30天以上

C．15天以上

D．5天

E．5～10天内