[单项选择]

The warming of the Earth (1) over the last 100 years will be due to a combination of many factors. Warming due to the increase in greenhouse gases (2) determined so far. (3) , projections of greenhouse warming do not rest on recent observations, they come from (4) understanding of the climate system. A (5) of simple and complex computer models (6) over the last 30 years to put together knowledge of many climate processes.
(7) to some scientific opinion, current models do a reasonable job of (8) today’s climate. The difference between summer and winter temperatures, in (9) to change in heating from the Sun, is correctly stimulated to (10) about 0.5 degrees over much of the planet. (11) events provide additional tests of our understanding. For example, the scale and (12) of cooling due to the eruption of Mr. Pinatubo were (13) by climate models.
W
A. directed
B. created
C. made
D. reproduced

The warming of the Earth (1) over the last 100 years will be due to a combination of many factors. Warming due to the increase in greenhouse gases (2) determined so far. (3) , projections of greenhouse warming do not rest on recent observations, they come from (4) understanding of the climate system. A (5) of simple and complex computer models (6) over the last 30 years to put together knowledge of many climate processes.
(7) to some scientific opinion, current models do a reasonable job of (8) today’s climate. The difference between summer and winter temperatures, in (9) to change in heating from the Sun, is correctly stimulated to (10) about 0.5 degrees over much of the planet. (11) events provide additional tests of our understanding. For example, the scale and (12) of cooling due to the eruption of Mr. Pinatubo were (13) by climate models.
W
A. observed
B. observing
C. to observe
D. has been observed