________our earth，or else it will be no longer fit for us to live on.
| A．Protecte | B．To protect | C．Protecting | D．Protect |
What the doctors really doubt is ____my mother will recover from the serious disease soon .
| A．when | B．if | C．whether | D．what |
--I like Tom very much _____he sometimes gives me some trouble.
-- Oh, it’s unbelievable.
| A．even if | B．as if | C．even now | D．as though |
Our English teacher advises us ____________ more after class.
| A．to practice to speak | B．practicing to speak |
| C．to practice speaking | D．practicing speaking |
— How was your weekend?
— Great! We ______ a picnic by the lake.
| A．have | B．are having | C．had | D．will have |
______ get a better score, she has been studying hard all day.
| A．So as to | B．In order to |
| C．So that | D．In order that |