天然气主要由()、乙烷、丙烷和丁烷组成。
参考答案:甲烷
.
"The house _________ go to the daughter, not the son, according to the will of the father, "declared the judge.
A.may
B.should
C.must
D.shall
稽留热,多伴有口唇疱疹,痰呈铁锈色,X线片呈片状淡薄炎症病变,边缘模糊不清。( )
A.空洞性肺结核,继发感染B.支气管肺癌C.囊肿继发感染D.肺脓肿E.细菌性肺炎