5道英语单选题,请英语高手进21.Isn’t it about the time you__________to do

5道英语单选题,请英语高手进
21.Isn’t it about the time you__________to do morning exercises?
A.began
B.begin
C.should begin
D.have begun
22.I am very grateful to you for what you’ve given me and__________you have done for me.
A.which
B.that
C.all what
D.all that
23.It was not until she had arrived home _____ remembered her appointment with the doctor.
A.when she
B.that she
C.and she
D.she
24.Determined to__________as if everything were normal,he responded with a kind of indifference.
A.carry on
B.account for
C.bring up
D.get through
25.He__________to arrange a loan through a finance company.
A.tried
B.succeeded
C.managed
D.endeavored