7、 The treatment will continue until the patient reaches the point ________ he can walk correctly and safely.
A. when B. where
C. which D. whose
8、 There are several research centers in China ________ a certain disease called Bird Flu is being studied.
A. which B. where
C. when D. what
9、 I hope that the little ________ I have been able to do does good to them all.
A. which B. what
C. that D. when
因为当先行词是表示事物的all, little, few, much, anything, everything, nothing等时，多用that引导定语从句。