Owls are poor home builders. They prefer to nest in a large hollow in a tree or even to occupy the deserted nest of a hawk or crow. These structures are large and rough, built of sticks and bark and lined with leaves and feathers. Sometimes owls nest on a rocky ledge, or even on the bare ground.
The mother lays two or three round, dull white eggs. Then she stoically settles herself on the nest and spreads her feather skirts about her to protect her precious charges from snow and cold.
It is five weeks before the first downy white owlet peeks its way out of the shell. As the young birds feather out, they look like wise old men with their wide eyes and quizzical expressions. They clamor for food and keep the parents busy supplying mice, squirrels, rabbits, crayfish, and beetles. Later in the season baby crows are taken. Migrating songsters, waterfowl, and game birds all fall prey to the hungry family. It is nearly ten weeks before fledglings leave the nest to search for their own food. The parent birds weary of family life by November and drive the young owls away to establish hunting ranges of their own.
What is the topic of this passage?
A.Raising a Family of Great Horned Owls
B.Mating Rituals of Great Horned Owls
C.Nest Building of Great Horned Owls
D.Habits of Young Great Horned Owls
第2题
紫外一可见分光光度法中,一般供试品溶液的吸光度应在
A、0.2~0.6
B、0.2~0.7
C、0.3~0.5
D、0.3~0.7
E、0.3~0.8
第3题
用紫外分光光度法进行药物含量测定时,供试品溶液的吸光度范围宜在
A、0.1~1.0
B、0.3~0.5
C、0.5~1.0
D、0.1~0.3
E、0.3~0.7
第5题
紫外-可见分光光度法中测定供试品溶液的吸光度值以在()之间为宜。
A.0.3-0.7
B.0.3-0.8
C.0.2-0.8
D.0.2-0.7
第8题
分光光度法中,常用的吸光度读数范围为
A、0~0.2
B、0.1~0.3
C、0.2~0.7
D、0.3~1.0
E、1.0~2.0
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