请根据下列材料回答问题：影响种群基因频率的因素有很多，如自然选择、基因突变、基因重组

上海世博会志愿者招募工作已于2009年5月1日启动，预计总共招募170000人，将170000这个数用科学记数法表示正确的是[ ]

A.0.7×10⁶

B.1.7×10⁵

C.1.7×10⁴

D.17×10⁴

假如有一天你去参观刚刚出水的宋代古沉船——“靖远一号”文物展览，你一定不会看到：[ ]

A、吴国的青瓷羊

B、唐朝邢窑白瓷

C、宋朝冰裂纹瓷器

D、明朝青花海水行龙纹扁瓶

TIPPING

How much and who on your cruise(乘船旅游) should be tipped? When and how should tips be given? Generally, you should plan to tip your room steward (服务员) $3.00 to $3.50 per person, per day, and plan an equal amount for your dining room waiter, and half of that for the busboy（餐厅侍者助手）.

On most ships, tip the maitre d’(侍者总管) or dining room captain only if you ask for special favors or table-side service; $5 to $10 is normal. Barmen and wine stewards are tipped 10 to 15 percent, but many cruise lines will add this tip to your bar or drink bill. Check the bill to see how it is handled. Also, tips for special services such as salon && spa treatments and room service are left to the guest, depending on services offered. Sometimes tips are placed in envelopes from your cabin’s stationery supply. Generally, passengers on cruises of 10 days or less will tip at the end of the cruise； on longer voyages, tipping weekly.

As part of a new trend that seems likely to grow, Carnival, Holland America, Norwegian, Princess and Cunard now charge tips to your account (账). Norwegian, for example, charges $10 per day, per guest, to cover service in the various dining rooms and your room steward. If you feel this amount needs to be increased or decreased, arrangements can be made onboard the ship, generally at the end of your cruise.

A few lines do not encourage tipping, including Radisson Seven Seas, Seabourn, Silversea and Windstar. Crew members are reportedly higher paid and not tip dependent. Many passengers tip anyway for outstanding service or special favors and give them tips face to face immediately they get serviced.

Tips on Tipping

Cabin steward

$3.00 to $3.50 per person per day

Waiter

$3.00 to $3.50 per person per day

Assistant waiter

$1.50 to $2.00 per person per day

Bartender, wine and deck stewards

10-15% of the bill

Maitre d’

$5.00 to $10.00 tip for each special service

小题1:According to the passage, if your bill for bartender and wine is $50, you will probably tip the steward ______.

A．$3.50

B．$3.00

C．$6.50

D．$10.00小题2:How many ways does the passage mention on how to tip the waiters?

A．3.

B．2.

C．4.

D．5.小题3: According to the passage, which of the following is NOT true?

A．Sometimes you must spend more money tipping waiters on cruise.

B．In the line Seabourn, you must tip crew members for the special service.

C．In some lines, you can bargain on how much to tip.

D．Generally speaking, maitre d’ can get the most tips.小题4:The passage is written mainly for the readers who are ______.

A．travelers on cruise to America

B．students to foreign countries to study

C．tourists not knowing how to tip in hotels

D．travelers on cruise the first time

工作必要性和工作班人员是否适当和足够是（）安全责任。

A、工作负责人

B、工作票签发人

C、工作许可人