How much sleep do the average teens need? ( )

(单选题)What was the author’s purpose when writing this passage? ( (单选题)A good gardener prunes a tree ( ). (单选题)Why is a special material painted on the tree? ( ) (单选题)Trees become unhealthy if the gardener ( ). (单选题)Why should pruning be done? ( ) (单选题)What is the attitude of Governor Stanforth Thumper toward th (单选题)With whom were the jails and courts overloaded? ( ) (单选题)Which of the following was NOT mentioned as a reason for the (单选题)Who had gas masks? ( ) (单选题)What were the demonstrators protesting about? ( )