The output of steel has doubled this year.[ ]

填入下面一段文字横线处的语句，最恰当的一句是 （ ）血栓闭塞性脉管炎又称“脉管炎”，虽是一种血管的炎症，但并不是细菌感染引起的的，而是血栓阻塞血管、血流减少所致，主要以下肢为主。脉管炎后期可引起手足发黑、坏死。但 ，如果在早期能明确诊断，及时治疗，可以避免发生严重的后果。

"We will learn Englishwords this year," the teacher said to the students.

Linda is ill again.—Yeah. She used to___________ in Hawaii and she doesn’t get used to__________here.

.—______ are you going with for vacation —My parents.