4－____=3
John ________ play the guitar, but he wants to join the guitar club.
—Would you mind staying in such a noisy room?
—No, but my son needs a _________ place to study in.
下图是一个算法的流程图，最后输出的W=( )
，那么播下4粒种子恰有2粒发芽的概率是（ ）
