F2 IS WS03 Answers

1st Term WS 03 Submission date：_____________ Name：______________________ Class & no.：2 _________(     )

7.1       What is air made up of?

B. Breathed air and unbreathed air

i      Words to know:

	English term	Write the words again	Chinese term
1	Breathed air		呼出的空氣
2	Unbreathed air		未吸入的空氣

i      Fill in the blanks:

The table below shows the comparison比較 between unbreathed air and breathed air:

	Unbreathed air	Breathed air
Nitrogen	About 78%	The same (about 78%)
Oxygen	More	Less
Carbon dioxide	Less	More
Water vapour	Variable多變的	More
Temperature	Lower	higher

i      Writing skill:

           Fill in the blanks and write sentences about the comparison between unbreathed air and breathed air. You may use the words ‘more’, ‘less’, ‘higher’ and ‘lower’.

1        (a)     Compared with breathed air, unbreathed air has more oxygen.

(b)     Compared with breathed air, unbreathed air has less carbon dioxide.

(c)     Compared with breathed air, unbreathed has less water vapour.

(d)     Compared with breathed air, unbreathed has lower temperature.

2        (a)     Compared with unbreathed air, breathed air has less oxygen.

(b)     Compared with unbreathed air , breathed air has more carbon dioxide.

(c)     Compared with unbreathed air, unbreathed has more water vapour.

(d)     Compared with unbreathed air, breathed has higher          temperature.