单项选择题

The doctor will not perform the operation______it is absolutely necessary.

A．so
B．if
C．for
D．unless
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单项选择题
Evidence came up______specific speech sounds are recognized by babies as young as 6 months old.
A．where
B．that
C．which
D．what
单项选择题
He______when the bus came to a sudden stop.
A．was almost hurt
B．was almost to hurt himself
C．was almost hurt himself
D．was almost hurting himself
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