99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

<pre id="zhezs"><strong id="zhezs"></strong></pre>

單項選擇題

Every precaution must be taken to avoid （）.

A.sparking being taking place
B.to spark taking place
C.sparking to be taken place
D.sparking taking place

你可能感興趣的試題

單項選擇題

It is obvious that the expansion of the water （）the increase of its temperature.

A.is due to
B.dues to
C.is because
D.is for

單項選擇題

An engineer, together with some motormen （）to help in the repair work.

A.send
B.sends
C.was sent
D.were sent