云贵高原地区土地利用中最主要的不利因素。
参考答案:
①山地多,平地少,耕地面积少;②喀斯特地貌广布,地层贫瘠,水土流失严重。
用所给单词的适当形式填空(每题3分)
小题1:I love places where the people are really _ (friend).
小题2:I want to go there, because I like ________ (excite)vacations.
小题3:Could you please give me some ________ (suggest)for vacation spots?
小题4:Would you like ________ (drink)some orange juice?
小题5: You look tired, why not ________ (have)a short rest?
小题6:His brother is considering ________ (study)abroad.
小题7:They _______(trek) through the jungle last vacation.
小题8:I’m________(save)my money so I can buy a new bicycle.
小题9:Many students are willing to _________(work) hard to have a good education.
小题10:Tom continued ________(do) his homework after he finished English.
支气管哮喘患者呼吸困难的特点为()
A.间断性吸气性呼吸困难
B.持续性吸气性呼吸困难
C.反复发作性呼气性呼吸困难
D.间歇性叹息性呼吸困难
E.反复发作的混合性呼吸困难