下列哪些化学物质易于从呼吸道进入机体（）。 A.苯 B.CO C.SO2 D.粉尘

根据材料内容选择最佳答案，并将其标号填人题前括号内。
Travel Arrangements（安排）
Date: 30 April, 2012                           For: Wang Mei

May 4	Leave Beijing Air China Flight CA 111 Confirmed（确认） Please check-in（办理手续）at least two hours before leaving time	10: 00 am
May 5	Arrive in Sydney Hotel bus will take you to the hotel	9：30 am
May 5	Holiday in Sydney Confirmed In: 5 May, 2012   0ut: 10 May Nights: 5
May 10	Own arrangement with host family
May 14	Leave Sydney Qantas Airline Ltd Flight QF 333	12: 30 p．m
May 14	Arrive in Perth The guide will collect you from the airport for four days return bus trip to Monkey Mia	15: 30 p．m
May 18	Leave Perth Qantas Airline Ltd Flight QF 444 Confirmed	11: 00 a．m
May 18	Raffles Hotel, Singapore In: 18 May, 2012  0ut: 19 May Nights: 1
May 19	Arrive in Beijing	16: 00 p．m

小题1:How many days will Wang Mei's holiday last?

A．14.

B．16.

C．19.

D．20.

小题2:At what time does Wang Mei have to be at the airport for her flight from Beijing?

A．8: 00 a. m.

B．9: 30 a. m

C． 10: 00 a. m

D． 11: 00 a.m

小题3:When she arrives in Perth, Wang Mei will travel from the airport _______.

A．by taxi	B． in a car
C．on the travel-bus	D． with her host family

小题4:Where will Wang Mei be on May 16?
A.  In a hotel in Perth.        B.  On her return to Sydney.
C  On a flight to Singapore.     D.  On a trip to Monkey Mia
小题5:In which country will Wang Mei stay before she returns to Beijing?           

A．Perth.

B．Sydney.

C．Singapore.

D．Monkey Mia.