【多选题】有关铝及铝合金焊接,以下说法哪些是正确的()
A.
可使用TIG 、MIG焊接铝及铝合金,通常MIG焊可焊接的母材板厚较大
C.
TIG焊时在纯氩气中加入氦气可降低预热温度及提高焊接速度
【单选题】The couple _____ some money every month for their future use even though their income can only make ends meet. [ ]
【单选题】What should we do even though some business trips may include more casual situations?
A.
Use proper casual language.
B.
Brash up on table manners.
D.
Represent your company.
【单选题】对2号图纸,图框线离图纸左边缘的距离及其余三边距离分别为( )mm
【单选题】下列有关氮芥类抗肿瘤药物的叙述不正确的是
C.
双β-氯乙氨基是抗肿瘤活性的功能基,属于烷基化部分
D.
改变载体部分,可以提高药物的选择性,降低毒性