1dig vi.& vt.挖(洞，沟等)
[观察] I like digging in the garden.我喜欢在花园里挖洞。The students will dig holes to plant trees this weekend.这个周末学生们会挖坑种树

[探究|dig的过去式和过去分词均为_dug，现在分词为digging
[搭配] dig up发现;掘起;掘地

1.(1)They_ dug _(dig) a hole to put in the tree just now.(2)2016·苏州Early this morning I was busy_ digging_(挖) inthe garden to plant trees.

2serious adj.认真的，严肃的
观察 Are you serious?你是认真的吗?
More and more families own cars and this causes serious air pollution.越来越多的家庭拥有私家车，这造成了严重的空气污染。

[搭配] be serious about..对…….认真
[拓展] serious的副词形式为_seriously ，意为“认真地，严肃地;严重地”。