69. Some parents are only concerned __ their children's grades in studies.
A. of
B. at
C. about
D. for
70. This disease __ itself in yellowness of the skin and eyes.
A. manifests
B. modifies
C. magnifies
D. exposes
71. Dr. Wang has made much contribution to the theories of modem physics at the __ of his health.
A. cost
B. disposal
C. mercy
D. expenditure
72. If I take this medicine three times a day, it should __ my cold.
A. heal
B. cure
C. treat
D. recover
73. Crisis would be the right term to describe the __ in many animal species.
A. abolition
B. restriction
C. descent
D. decline
74. Up until that time, his interest had focused almost__ on fully mastering the skills and techniques of his craft.
A. restrictively
B. radically
C. inclusively
D. exclusively