Before the first non-stop flight made in 1949, it______necessary for all planes to land for refueling.

that all the risks should be calculated in advance. A: This is necessary B: Which is necessary C: That is necessary D: It is necessary

We consider _____ lessons should be previewed before the class. A: that it necessary B: it that necessary C: it necessary that D: necessary it that

I find ____________ to make some changes. A: it is quite necessary B: that is quite necessary C: it quite necessary D: quite necessary

If_____, we’ll continue our experiment after office hours. A: being necessary B: be necessary C: is necessary D: necessary

If_____,<br/>we’ll continue our experiment after office hours. A: being necessary B: be necessary C: is necessary D: necessary

We consider ____university students should do more reading during their spare time. A: necessary that B: necessary C: it necessary D: it necessary that

在学校克服害羞是必要的。 A: It is necessary to treat shyness at school. It is necessary to wipe out shyness at school. B: It is necessary to overcome shyness at school. C: It is necessary to deal shyness at school.

在学校克服害羞是必要的。 A: It is necessary to treat shyness at school. B: It is necessary to dealshyness at school. C: It is necessary to overcome shyness at school.

Rewrite the following, using be-subjunctive:It was necessary for him to leave immediately.It was necessary that he ____ immediately.