v. + problem >>共 361
have 22.63%
solve 9.06%
cause 5.52%
face 3.36%
address 2.77%
create 2.61%
pose 2.36%
fix 2.32%
resolve 2.12%
discuss 1.64%
study 0.42%
study + n. >>共 873
issue 3.58%
way 2.85%
possibility 2.50%
proposal 2.20%
law 2.06%
effect 1.78%
problem 1.34%
art 1.30%
history 1.19%
report 1.16%
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