unit 3 amazing people ⅰ.单项填空 1.i know that when he looks at his watch,it's a ________for us to start the attack. a.sign b.expression c.meaning d.signal 答案 d [句意:我知道当他看手表的时候就是要我们开始进攻的信号。signal信号,符合题意。] 2.now a lot of new technologies can ________problems in industry. a.be applied to solve b.be applied to solving c.apply to solve d.apply to solving 答案 b [考查动词搭配。apply...to...表示“把……应用到……