单项选择题 Crack growth rates are initially high but decrease, with the decreasing crack length. （ ）A.对B.错
单项选择题 Recording estimated warranty expense in the year the related products are sold best follows expense recognition (matching) of accounting principle.（ ）A.对B.错
单项选择题 In general, aggregate demand depends only on prices and total income and not on income distribution A. 对 B. 错