471-1 c- of 3 m- com-

2'

471-2 a dis- c-

1'

471-3 f- a c-

1'

471-4 pr-

1'

471-5 ex- ch- of n-

2'

472-1 the c- d- having a p-

2'

472-2 with a B- ex- of 9-v- b-

2'

472-3 and a sl- to in- the dis- car-

2'

472-4 con- over B- to dis- re-

2'

473-1 the problem of l- in drinking water

2'

473-2 water c- for about 2 yrs

2'

473-3 c- a d-

1'

473-4 fast l- and water testing

2'

474-1 the G- God- of fresh water

2'

474-2 de- whether the water is safe

2'

✨
以上为第一部分