标识词、特征词: now 、 look 、look at 、 listen 、 listen to 、 It’s+ 时间
构成:人 \ 物 +“be” 动词 + 动词 ing 形式 例如: (1) I am looking for my book now
(2) Listen , he\she is playing the guitar
(3) Look , they are swimming in the lake
否定形式:… am\is\are not + 动词 ing 形式 例如:( 1 ) I am not looking for my book now
( 2 ) Listen , he\she is not playing the guitar
( 3 ) Look , they are not swimming in the lake
一般疑问句: Is\Are… + 动词 ing 形式…
例如:( 1 ) Are you looking for your book now
——Yes , I am
/No , I’m not
( 2 ) Listen , he\she is playing the guitar
Is he\she playing the guitar
——Yes , he\she is
/ No , he\she isn’t
( 3 ) Look , they are swimming in the lake
Are they swimming in the lake
——Yes,they are
/No, they aren’t
动词变化: 动词末尾 +“ing” ( 1 )一般情况在词尾 +ing :例如: look—looking see—seeing ( 2