A Write one word in each gap.

SPACE PROBES BEHAVE STRANGELY
Is an unknown force having an influence (1)… Pioneer 10 and 11, NASA’s oldest space probes? The probes have been travelling through space for over thirty years, but scientists have now (2)….to the conclusion that their current position does not correspond (3)…..predictions of where they should be. The probes appear to be (4)….the control of something other than the sun’s gravity. Scientists are unsure of the cause (5)….the probes’ slowness, but have narrowed (6)…the possibilities to three main options. They (7)….forward their suggestions at a conference this week. It is possible, but unlikely, (8) both probes are malfunctioning in the same way at the same time; our understanding of gravity may be wrong, or an unknown force in the universe is (9)a difference to the speed of the craft. Scientists say they will need to carry (10)…….more research before they can determine what the cause is.

B Complete the sentences below by changing the form of the word in brackets when this is necessary.

11 No one knows what the real …….(explain) is.
12 From his…… (appear), you would think that Adam is lazy, but he’s not.
13 The prime minister is going to make an…. (announce) this afternoon.
14 Gordon’s got a great sense of …. (humour).
15 Let’s have a more detailed …. (discuss) about that later.
16 We’ll have to get a lot more …. (inform) before we make a final decision.
17 The … (invent) of the wheel changed the world enormously.
18 I’m going to write a letter to the …. (edit) about that article.