Vacation schools and extracurricular activities are mentioned in Para. 2 to illustrate alternatives to formal education pro- vided ______ by public schools.
A. the importance of educational changes
B. activities that competed to attract new
C. immigrants to their programs
D. the increased impact of public schools on students
硝酸甘油影响最小的血管是
A. 小动脉
B. 小静脉
C. 冠状动脉的阻力血管
D. 冠状动脉的侧枝血管
E. 冠状动脉的输送血管
The word "diffuses" in Para. 3 is closest in meaning to ______.
A. yields
B. starts
C. surfaces
D. travels
What should a driver do when ascending
A. Rise slowly.
Breathe faster.
C. Relax completely.
D. Breathe helium.
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