A． just reads about other people's observations and discoveries
B． comes up with solution in most natural ways
C． has a great deal of trouble doing mental arithmetic
D． lacks some of the qualities required of scientist
A． he didn't live very long with them
B． he was fully occupied with observing nature
C． the family was extremely large
D． he was too young when he lived with them
A． The author believes that a born naturalist can not be a scientist
B． The author read a lot of books about the natural world and oil industry
C． The author's brothers and sisters were good at music and languages
D． The author spend a lot of time working on riddles
A．have been put in
B．being put in
C．has been put in
D．to be put in