Nothing But Trouble, Trouble, Trouble

Though Alex very badly wants to be grown up, especially to embark on a baby-sitting career lucrative enough to pay for pierced ears, she has an unmistakable propensity for trouble. After an escapade involving her younger sister, Meg, and a great deal of mud, Alex agrees to prove her trustworthiness to her parents. First, she will earn an A on a ``responsibility project'' for her fifth-grade science project (involving tending either a pet or an egg for a whole weekend, ``like, all the time ''); second, she will keep out of mischief for two weeks. Deciding that she'd rather watch a pet than an egg, Alex catnaps two felines from an out-of-town classmate--despite her keen awareness of Meg's serious allergies. Alex's glaring lack of judgment and absurd short-sightedness are too obviously at odds with her goals, and it's hard to care much about her. On the other hand, her older brother, ``Mr. Perfect,'' a marvel of academic and social achievement, seems little more than a stereotypical good kid, serving chiefly as a marked contrast to his sister. The broad humor and high jinks that mark this tale are simply not enough to carry it. Ages 8-12. (Mar.)