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

<progress id="undn5"></progress>

<ruby id="undn5"><xmp id="undn5"></xmp></ruby>

單項(xiàng)選擇題

In the International Code of signals，a group of three letters indicates（）.

A.urgency or an emergency
B.the vessel's national identity signal
C.a group from the general signal code
D.a group from the medical signal code

你可能感興趣的試題

單項(xiàng)選擇題

In order to prevent galvanic corrosion，an aluminum boat must be insulated from the davits and gripes. Which of the following is acceptable as an insulator?（）

A.Hard rubber
B.Canvas
C.Leather
D.Sponge rubber

單項(xiàng)選擇題

In battery charging rooms，ventilation should be provided（）.

A.at the lowest point
B.near the batteries
C.at the highest point
D.only when charging is in progress

<ruby id="pem3i"><xmp id="pem3i"></xmp></ruby>

<ruby id="pem3i"><xmp id="pem3i"></xmp></ruby>

<dl id="pem3i"></dl>

<blockquote id="pem3i"><acronym id="pem3i"><div id="pem3i"></div></acronym></blockquote>

<ruby id="pem3i"><small id="pem3i"></small></ruby>

<ruby id="pem3i"><xmp id="pem3i"></xmp></ruby>